College of Gardening

Raised Garden Beds

What is a raised bed?

A raised bed is a mound of soil in which gardeners plant their crops and flowers. Many raised beds are framed or enclosed. Frames help keep the soil in place during rainstorms and watering.

What are the benefits of a raised bed?

• Once the soil is prepared, you don’t have to walk on it again during the growing season.
  Make sure the beds are no more than two arm lengths wide, so that you can reach everywhere within the bed without stepping in it.
  You can work in the garden in wet weather without getting your feet wet or compacting the soil.
• If you have contaminated or poor soil, it’s easier to bring in good soil to create a raised bed than to amend the soil in the whole area. In soggy areas, the soil in raised beds will drain more quickly.
  Raised beds are ideal for gardening on rubble-filled city lots.
• The soil in raised beds warms up earlier in the spring and stays warm longer in the fall. This extends the growing season.
• It’s easier to tend the garden when it is raised above ground level, because you don’t have to do as much bending.
  Gardening in raised beds that are 30 cm high is easier for disabled and elderly gardeners.

How do you build a raised bed?

1. Making a raised bed on a city lot
   Use string to mark off where the bed will be. Use a pickaxe to loosen up hard, compacted soil and rubble in the bed. This will help the bed drain, and will allow roots to grow deeper. Have good topsoil delivered to the site. Work some of the topsoil into the existing soil to a 15 cm depth. Build the frame around the bed, and fill it with soil.
2. Making a raised bed using existing soil
   Rake the soil from the walkways to the top of the bed. Make the soil mound about 15 cm high. To make the bed more permanent, build an edge with wood planks, or another material that will keep the soil in place.
3. Making a raised bed frame
   You can build the sides of a raised bed out of cinder blocks, stones, or landscape timbers. Do not use treated lumber or railroad ties. They contain poisons that you do not want in your garden soil. Hold the planks in place with stakes or steel rods or pipes. You can also use wood screws to fasten the corners together. Do not use nails, as they might split the wood.
4. Preparing soil
   Mix lots of compost or other organic matter into the soil in your raised bed. Flatten the top with a rake before planting. You can plant crops closer together than in a regular garden. You do not need space between rows of plants, because you walk outside the beds.

Look and learn about raised beds in your community

1. Watch people working in the raised beds. List some of the pros and cons that you think this system of gardening might have for gardeners.
2. Are the raised beds surrounded by an edge? If so, what material is being used for the edge? What are the advantages or disadvantages of this material? Can you think of a different material that might be better for the edge?
3. With permission from gardeners, observe the condition of the soil in the raised beds. Is the soil better than the soil that is not in raised beds? Does the soil in the raised beds have more organic matter? (Is it darker in color?) Are there more earthworms and other soil organisms? Does the soil have a better texture, pH, and drainage? (You can find directions for doing soil tests in the Water in Soils, Soil pH, and Soil Texture Science Pages.)
4. Look at the plants growing in the raised beds. Does the raised bed system seem to be meeting the needs of the plants? Would it be possible to grow the same plants at that location without raised beds?
5. Summarize your findings in a report to your group. Answer the question: How useful are raised beds in community gardens?

Spotlight on research: Ancient raised bed methods still work wonders!

Before the arrival of the Europeans in 1492, ancient raised fields covered 1,000 square kilometers of Latin America. The raised fields were about 3 meters wide, and lay between canals. The canals had a number of useful purposes. The water in the canals could be used for watering the raised fields during dry periods. The water also kept the temperatures around the fields higher during cold weather, and so kept the crops from freezing. And the canals produced organic muck that could be used to fertilize the raised fields. It is believed that the canals even may have been used to raise fish and useful water plants.

Scientists wondered if these ancient farming techniques might be useful for farmers today. To find out, they began the Raised Field Agriculture Project. The project took place in the Lake Titicaca Basin in Peru and northern Bolivia. This is a very difficult area for farming. It is located 3,810 meters above sea level in the Andes Mountains. The soil is very poor, and there are frequent frosts, hail storms, floods, and droughts. Despite these limitations, the area supported dense human populations for thousands of years before the Europeans arrived. Scientists on the research team included archeologists, soil scientists, and horticulturists. Archeologists researched how the ancient raised fields and canals were built. Soil scientists investigated how the soil in the raised fields could be improved. Horticulturists and local farmers rebuilt the raised fields and planted potatoes. The results were astonishing. The raised fields yielded two to three times more potatoes than other farms in the area!
Source: Erickson, C.L. (1988). Raised field agriculture in the Lake Titicaca Basin: putting ancient Andean agriculture back to work. Expedition 30 (3), 8-16. Special issue on Andean Archaeology. Mohr Chavez, K. (Ed). The University Museum, University of Pennsylvania, Philadelphia

Information from Garden Mosaics (www.gardenmosaics.org)

Garden Mosaics is funded by the National Science Foundation Informal Science Education program, and by the College of Agriculture and Life Sciences at Cornell University.

Soil Prep

Clearing the Site

In an earlier unit on creating a budget and timeline, the idea of site development was introduced. In this section, budget items were created for clearing/scraping the site. We will now talk more in depth about these topics.

• Removal of Debris: Debris can include both man-made and natural objects. It is not uncommon to find trash and leftover building materials; it is also just as common to find rocks, boulders and tree stumps that will keep you from being able to grow. All of these items need to be removed before you can develop the site.
• Weeding: Grass, weeds and small unwanted trees should be removed before soil prep is begun. Tilling under weeds that might have seeds or aggressive roots is not recommended.
• Hand Pulling: Weeds can be removed by hand if they are already growing on the site. In the tools section, we will discuss appropriate tools for this job.
• Herbicides: If you are able to use pre-emergent herbicides (sprayed on the ground before the weeds start to grow), there are many organic brands available. This will only work if you are able to access the site before the growing season.
• Sod Cutting: If the site has a lot of grass, a sod cutter might be the best option. Sod cutters can be manual (a hand tool) or mechanical (a larger piece of machinery) and they usually remove about the 4-6 inches of grass/soil.
• Black or Clear Plastic: Another method for removing weeds if you have a longer time period is to cover the ground in black or clear plastic. Over time, the sun heats the plastic and kills all plants and seeds beneath. This process can take a few months.

At a Glance

Compact Soils

Plant growth is affected by the level of compaction in the soil. Very compact soils don’t allow space for roots to grow; if roots stay small, plants grow shorter and even the leaves grow smaller. The best way to fix compaction is to mix compost into the soil. The act of mixing (or tilling) breaks up the compaction and the compost keeps the compaction from happening again.

Preparing the Soil

Farmers usually prep their growing beds right at the beginning of the season. This is a good time to add amendments (see next unit) and to loosen the soil in case any compaction occurred over the winter. Sometimes prep and amending are done in the fall, as well. There are multiple methods of prepping the soil.

• Tilling: Tilling is usually done with a rototiller or sometimes even larger machinery like tractors. Tilling adds air to the soil and breaks up any compaction. However, it should not be done when the soil is wet or it might actually create compaction.
• Double Digging: this is a similar process to tilling, but it is done by hand. When gardeners double dig, they are digging roughly two shovel lengths down into the ground to loosen the soil (that’s where the double comes from). It can take a lot of time and be physically difficult if you have a large area to prep.
• Cover Crops/Green Manure: This is a process that is used with double digging or tilling that also adds a fertilizer. In the off-season, special crops that are high in nitrogen and other nutrients are grown (such as hairy vetch, peas and winter rye). Right before the season starts, the crop is cut down and either dug or tilled into the soil.
• Lasagna Layering: Some gardeners prefer a method of soil prep that requires no digging and no machinery. With the lasagna method, layers of newspaper, compost/ manure, and leaves/straw are laid directly on the ground and are left to sit for a few months or until they decompose naturally. This provides a very healthy growing space for plants.

Source: Urban Botanical University/Denver Botanic Garden
Unit 2 Chapter 1
Author: M. Bumgarner  

Choosing Crop Varieties

Types of Crops

In urban agriculture, a crop is a plant that is grown for food. Other types of farms might have crops that are grown for textiles (such as cotton and hemp) or for flower production (cut flowers, potted plants, etc.).

Different crops are harvested from different parts of the plant.

For example:

• Roots/bulbs: beets, carrots, potato, garlic, etc.
• Stems/flowers: broccoli, cauliflower, etc.
• Leaves: spinach, lettuce, kale, chard, etc.
• Fruits: tomatoes, peppers, melons, eggplants, etc.

Crops are also divided into categories depending on which time of year they are grown.

Cool season crops:

• Are planted in the early spring and fall when temperatures are between 40ᵒF and 60ᵒF.
• Grow during the cooler months and are harvested at the beginning of summer and the end of fall.
• Will not grow in warmer weather; they will bolt (develop flowers) much quicker in seasons with warmer temperatures.

Warm season crops:

• Are planted or sown in early summer when temperatures are above 60ᵒF.
• Are harvested in the late summer and fall. They must be harvested before the first frost because warm season crops die when temperatures dip below freezing.

Winter crops include:

• Garlic, which is planted in the fall and then grows throughout the winter for harvest in the spring.
• Perennial herbs and flowers. These plants aren’t harvested in the winter, but they will come back every year, so they may require extra attention during the cold months.

The table below is an example of crops that have been selected to be harvested in each of the three growing seasons:

Spring	Summer	Fall
Asparagus Broccoli Carrots Celery	Beans Beet Cucumber Eggplant	Beets Carrots Fennel Chard
Cauliflower Kale Lettuce	Garlic Kohlrabi Rhubarb	Leeks Parsnips Potatoes
Peas Radish Spinach	Onions Squash Zucchini	Pumpkins Tomatoes Squash

This list contains a lot of variety; remember that the vegetables harvested in spring and fall might be very similar.

At A Glance

Choosing crops for a farm is based on the amount of space available and the desired harvest. Answer the following questions to help determine which crops will meet these demands.

1. How much planting space is available?
2. How much of each crop do I want to harvest?
3. Can the seed be directly sown in the soil or does it need to be started indoors?
4. How much of the total space will the crop need?
5. What will be done with the harvest? (eat, share, donate, sell)
6. How will the harvest be stored? (canned, dried, frozen)

Reading a Seed Packet

The front and back of each seed packet provides the information needed to grow and harvest each crop.

The following information can be found on a seed packet:

Seed Origin:

• Heirloom: Varieties of seeds that are passed down from generation to generation, keeping the same characteristics from year to year. This beet is an heirloom.
• Organic: Grown within the standards of USDA organic produce. These seeds are not treated with any non-organic substances. This beet is also certified organic.
• Hybrid: A cross between two different parent plants. The hybrids are designed for specific characteristics like disease resistance, taste, or color. Hybrids can be organic if both parents are organic.

Cultivar or Variety

The back of a seed packet will describe the characteristics of the cultivar or variety that make it different from other seeds of the same vegetable. Information is given about the color, flavor, texture and uses.

Indeterminate or Determinate

• Indeterminate plants will grow and produce fruit all throughout the growing season until the frost kills the plants.
• Determinate plants only grow until they reach their mature height. These plants produce all of their fruit during a short period of time which provides one large harvest.
• The beets are determinate because they only produce one harvest per plant.

Vine or Bush

• Vining plants will grow vertically and will need a structure or another plant for support. These plants tend to produce a continuous crop.
• Bushing plants tend to be compact and grow to the size listed on the seed packet. They tend to produce their crop in a short period of time.

Planting Conditions

The back of most seed packets will have information about how a seed should be planted. The picture below is an example of how this information might look.

• Planting Depth (seed depth): the distance between the soil line and the bottom of the trench where the seed is planted. Planting too shallow or too deep will result in bad germination.
• Soil Temperature for Germination: the best soil temperature for a seed to germinate. If seeds are planted too early when soils are too cold, they can either rot or not germinate.
• Days to Germination (days to emerge): the number of days until the first sprout appears above the soil.
• Plant Spacing After Thinning: the distance between each plant that will prevent crowding and wasting space. When sowing seeds, more seed are sown than needed in case some don’t germinate. Once they have germinated, the seedlings are thinned to the recommended distance.
• Days to Maturity: the time it takes for a seed to mature to a plant that is ready to be harvested.
• Light Requirement: the ideal amount of sunlight the plant needs to grow. Full sun is equivalent to 8 hours of sun a day, part sun is 4-6 hour, and shade is fewer than 4 hours of sun.
• Water Requirement: the ideal amount of water a plant needs to grow.
• Number of Seeds per Packet: helps determine how many packets of seed are needed to fill a certain area.

Source:Urban Botanical University/Denver Botanic Garden
Unit 3 Chapter 2
Author: J. Casault

Germinating and Growing on

Materials

The following materials are necessary for starting seeds; materials can be store-bought, but many can be improvised from materials around the house:

• Seeds
• Labels: Plastic or metal store-bought labels, popsicle sticks, venetian blinds cut into sections
• Germinating Mix: Storebought or homemade, the most important qualities of a good germinating mix are small particle size and lots of water and air space. Particle size should be small enough
• that a germinating seed won’t have any trouble pushing through the surface of the mix.
• Containers: Store-bought containers are usually made of a nursery-grade plastic, Styrofoam, or peat moss. Recycled containers, such as yogurt cups or egg cartons, can also be used, but they should be clean and holes may need to be added to allow for drainage.

At a Glance

Most farmers buy germinating mixes, but they can be made at home. The following is a simple formula for germinating mix:

• 4 parts screened compost
• 1 part perlite
• 1 part vermiculite
• 2 parts screened sphagnum peat moss

Scheduling

To figure out when a plant needs to be started indoors:

1. Decide when the plant will be planted in the ground.
2. Subtract one week for hardening off (see next page).
3. Subtract the following number of weeks for each specific plant based on the list below:

• Brassicas (broccoli, cabbage, cauliflower, kale, kohlrabi, etc.): 4 weeks
• Mint family (basil, lemon balm, mint, oregano, sage, etc.): 4 weeks
• Squash Family (cucumbers, cantaloupe, summer squash, winter
• squash, melons, etc.): 4 weeks
• Lettuce: 3 weeks
• Onion family (onions, leeks, chives, etc.): 10-12 weeks
• Eggplants: 7 weeks
• Tomatoes: 6 weeks
• Peppers: 10 weeks
• Parsley: 10 weeks

It is useful to keep records of when seeds are sown, transplanted and planted outdoors to help stay on schedule and to compare from year to year.

Sowing Seed

When sowing seeds in seed trays or pots:

1. Fill the tray or pot all the way to the top with germinating mix. The mix should be moist, but not soaked and definitely not overly dry.
2. Make indentations in the soil where the seeds will be placed.
3. Check the seed packet for a sowing rate (how many seeds per cell). If there is no information, the following guidelines can be used:

• Large seed (such as beans, okra), 1-2 per cell
• Medium seeds (such as brassicas, lettuce, tomato), 2-3 per cell
• Very small seeds (such as mint), 45 per cell Sowing too heavily will cause crowding and seedlings will be weak.

4. Small seeds, like lettuce, basil and brassicas, will germinate better if they are sown on the surface and are not covered up. Larger seeds, like beans, squash/melon and chard, will germinate better if they are covered with germinating mix.
5. Thoroughly water the seed tray or pot after sowing and continue to check moisture

Transplanting and Hardening Off

Most plants will need to be transplanted to a slightly larger container in order to grow larger roots before they are planted outside. Seedlings are ready for transplant when they have their first set of true leaves and when there are enough roots to hold the germinating mix together in the container. Most plants will be transplanted at the same depth as the tray or pot in which they were germinated. However, brassica plants (broccoli, kale, cauliflower, etc.) and plants in the nightshade family (tomatoes, eggplants and peppers) will do much better if they are buried about half-way up the main stem (or hypocotyl).   Transplants are ready to go outside when

the roots are strong enough to hold the soil together when removed from the pot. Plants that have been grown indoors should be hardened off before being planted outside. Hardening off is a process of slowly adjusting plants to outside temperatures. While the plants are still in pots, they are left outdoors for a few hours during the daytime (in non-freezing temperatures) for about one week.

Source: Urban Botanical University/Denver Botanic Garden
Unit 3 Chapter 1
Author: B. Darby

Maintaining Moisture in a Raised Bed

Moisture levels

Maintaining even moisture levels in raised garden beds can challenging for the new community gardener. With enough organic matter and good watering habits, however, a raised bed can become a perfect controlled environment for building-up a garden’s moisture-retaining capacity.

Healthy soil structure and an evenly balanced, loamy texture (composed of different size soil particles) provide the ideal conditions for maximizing a raised bed’s water retention. Gardeners can strive to leave the soil undisturbed as much as possible.

Soil structure

Soil structure protects soil’s water retaining capacity and is improved the when gardeners refrain from double digging, stepping on wet soil in the spring, and pulling out annuals at their roots in the fall. Non-diseased plants can be cut off at the stem base and chopped up and left on the soil at season’s end to minimize erosion and disturbance of the pores created in the soil by plant roots and microbial life. These pores are essential to getting water into the soil and keeping it there. Collapsed and compacted soil lacks infiltration capacity so water runs over and off, rather than sinking into the soil. When water is able to freely enter micropores and macropores in the soil, it also aerates the soil by pushing out old air.

Mulch

Mulch improves water retention and reduces evaporation, while providing additional organic material to fuel biological activity in the soil. Straw, hay, and other “green” mulches like grass clippings and alfalfa meal, are excellent mulches for the vegetable garden because they favor bacterial activity in the soil. Cocoa-shell mulch is also a favorite for organic vegetable gardeners. Perennials and trees prefer shredded bark and other “brown” mulches that encourage increased fungal activity, but can cause nitrogren deficiencies in vegetable gardens. Encourage gardeners to apply mulches in layers about 2 inches thick and provide space around plant stems so that air and water can still penetrate the soil.

Proper spacing

Planting techniques and spacing also influence water availability as roots compete for moisture in the soil. Proper plant spacing gives seedling room to grow and keeps plants close enough together that bare soil does not lead to evaporation. Over-crowded plants struggle to get enough water because too many roots are competing in one spot, particularly in a raised bed with an impenetrable surface beneath the soil. Gardeners can give vegetables like tomatoes and cucumbers a head start in their quest to quench summer thirst by spacing them far enough apart. Their roots will be able to spread out further and extend each plant’s access to the moisture and nutrients available in the soil.

Intercropping

Quick growing, shallow-rooted annuals like lettuce, however, can be planted around young tomatoes and cucumbers in the spring as a shade canopy and living mulch. These early cover crops shade the soil while late summer plants are still small and minimize evaporation and nutrient loss that can result from bare soil. This practice, called intercropping, helps raised bed gardeners maximum their plots production without overcrowding the plants that are growing at the same rate and looking for the same nutrients.

The “Three Sisters” technique of intercropping corn, beans, and squash applies a related approach by using squash to act as a ground cover mulch and root stabilizer, while beans climb up the corn and lend their nutrient fixing roots and mychorrizae fungi nodules to provide fertilizer for the corn. With adequate nutrients and symbiotic microbial relationships, the three sister plants have an even greater capacity to maintain even moisture levels for their roots in the healthy balanced soil.

Good watering habits are more easily achievable with healthy soil and properly spaced, thoughtfully grouped plants. Once gardeners have learned how to build up soil structure and microbial life, their gardens will be able to hold on to more moisture from a heavy rain or deep watering. If the soil cannot support infiltration and the plants are spaced too close together, the gardener will feel like their soil is always dry and needs watering. Even if gardeners find they need to come water their raised bed every day in the heat of the summer, a deep thorough watering will promote more water retention and stronger, deeper roots for the plants.

Lesson plan

OBJECTIVES:

Teach gardeners that maintaining moisture in the soil requires more than watering every day.

Help gardeners understand that water is part of the soil’s composition and acts as an integral participant in the relationship between plants, soil, and microbial life.

MATERIALS NEEDED:

• Two watering cans filled with water — one with a rosette nozzle attachment, one without
• Three rimmed sheet pans or containers filled with soils with different structures
• A tall glass (see-through) jar or vase filled with potting soil

ACTIVITIES:

1. Ask gardeners how they generally water their plots. Discuss water flow rates, infiltration, and review how good soil structure helps maintain capillary moisture.

2. Demonstrate ways to test soil moisture below the surface with a finger test or by squeezing a bit of soil in a palm.

3. Demonstrate watering potting soil in a sheet pan or container with a rosette and without a rosette. Watering with a rosette mimics rainwater, a gentle sprinkling of water which greatly preserves the air spaces in the soil. Flooding the soil with water from a non-rosette watering can fills in those spaces, and with some types of soil such as a highly-clay soil, can contribute to compacting over time. The way the soil sinks and becomes much more dense when watering without a rosette is very obvious within a few seconds, whereas watering with a rosette provides a slower flow and better infiltration.

4. Discuss the effect of watering at different times of the day on the soil vs. on the leaves. Demonstrate why a rosette would be better for watering seedlings or applying foliar feed fertilier, and why this would be best done in the morning or evening to avoid scorching of the leaves in the sun. Demonstrate how to water the soil only during regular watering to minimie susceptibility to pathogens growing on wet leaves.
5. Demonstrate infiltration differences by watering different types of soil in the garden or in sheet pans and observe how the soil is absorbed.

6. Demonstrate the difference between shallow frequent watering and deep watering with the tall glass jar or vase filled with potting soil. Water a small amount a few times so gardeners can see how little the water pentatrates into the soil even though the surface is wet. Wait for 5 to 10 minutes, then apply a larger amount of water (preferrably with a rosette nozzle) and allow gardeners to watch the water penetrate the potting soil and slowly reach the bottom of the jar or vase. Discuss reasons why applying more water less often could be more beneficial than watering a small amount every day. Deeper watering encourages roots to seek water further down in the soil, rather than at the soil surface, and deeper roots greatly reduce drought stress.

Source: Environmental Education in the Community Garden materials were produced by the American Community Garden Association (ACGA). ACGA acknowledges EE Capacity, Cornell University, Civic Ecology Lab, United States Environmental Protection Agency, North American Association of Environmental Education, and Peterson Garden Project.

Inviting Pollinators into the Garden

Native pollinators

While bees do the majority of the pollinating work, other insects also act as pollen delivery agents in the edible garden. Native pollinators including flies, butterflies, beetles, wasps, and hummingbirds are also effective at sniffing out nectar and moving around pollen. In order to produce fruit or vegetables, many flowering plants require pollinators to move pollen from one flower of a species to another flower in order to produce fertile seeds.

Gardeners can attract pollinators to their garden by planting native flowers and herbs with showy flowers such as dill or pineapple sage. Native wildflowers are particularly effective in attracting native pollinators because they have evolved together and adapted to local conditions. Over the past fifty years, pollinator populations have declined due to habitat loss, use of pesticides, and pollution. Creating safe environments for these crucial organisms in community gardens benefits the ecosystem of the entire planet because all living animals on the food chain (including us) depend upon the foods produced by flowering plants.

Bees

Because they feed only on flowers, bees do the most crucial pollinating work in a garden. They collect nectar to fuel their work and proteinfilled pollen to feed their hive. In the process of sampling all of the flowers in garden, they provide invaluable pollination services for flowering fruits and vegetables. Around four thousand species of bees buzz through North America and are attracted to brightly colored and sweetly fragranced flowers. Bees are able to see ultraviolet colors, so are particularly drawn to yellow, orange, purple, blue and white flowers. Planting Black-eyed Susans, marigolds, salvia, alyssum, and flowering anise hyssop can help nurture busy, happy bees. Bees can also be found enjoying “weeds” such as dandelions and clover. They prefer flowers with short nectar spurs and easily accessible nectaries because the probobsis they use to reach into the flower is relatively short.

The leaf cutter bee uses composite flowers including Gallardia (blanket flower), asters, and sunflowers as a habitat in addition to pollen sources. A female leaf cutter bee will line her nest chambers in the soil with circular leaf cut-outs from these composite flowers.

Encourage bees with a diverse range of flowers that bloom at differenct times throughout the growing season. Leaving pieces of hollow twigs and a few branches on the soil provide plant material for nesting bees (70% of all bees). In addition to avoiding pesticides and chemicals, gardeners can encourage habitats for bees that nest in soil by making sure mulch levels are not too thick and providing small water supplies (a pollinator’s version of a bird bath).

Honey bee on milk thistle flower.

Butterflies and moths

Butterflies are attracted to yellow, red, and purple flowers with sweet scents. Native milkweed (Asclepias) provides pollen, nectar, and habitat for caterpillars. Nurturing habitats for desired caterpillars and larvae leads to a healthy and abundant butterfly population that will also help gardeners growing flowering vegetables like tomatoes and cucumber. Caterpillars will eat their host plants when they are born and can devour a lovage or parsley plant in a week or an entire row of legumes. Seeing this process as a necessary part of the pollination cycle will help gardeners be more respectful of the work swallowtails and monarchs do in the gardens.

Hummingbirds

Hummingbirds travel great distances in their search for delicious flower nectar. This makes them great pollinators because they move pollen in the process and increase biodiversity in plant species. Hummingbirds love red, nectar-filled flowers such as fuschia, canna, and honeysuckle and develop a territory path claiming the most delicious flowers in their daily path. WASPS, BEETLES & FLIES Flower beetles, pollen wasps and hoverflies disguise themselves to look very similar to many bee varieties as a defense mechanism while they feed on the same pollen preferred by bees. While they are less effective pollinators than bees, their movement of pollen in the garden aids the overall ecosystem of a healthy pollination system. These insects love native purple coneflower, sunflowers, yarrow, and other flowers with showy pollen displays.

Lesson plan: Be the bee

OBJECTIVES:

• Help gardeners see the garden through the “eyes” of a nectar- and pollen-hungry pollinator. Teach them how to nurture fragrant and bright native flowering plants as necessary partners in the edible food garden.
• Encourage gardeners to develop respect for pollinators while learning to understand how beneficial bees, wasps, and other insects promote plant development.
• Enhance gardeners’ understanding of ways that cucumbers (and other flowering vegetables) depend upon pollinators to produce our food.

MATERIALS NEEDED:

• A community garden or nature area thriving with flowering plants
• A sunny day

ACTIVITIES:

1. Walk through the garden and identify pollinators.

2. Ask gardeners to identify flowering plants in the community garden and discuss the importance of a flower’s shape, color, scent, and bloom time in aiding pollinators for different vegetable crops.

3. Encourage gardeners to pretend to “be the bee,” by discussing pollinator eyesight, which spectrums they can see, and the most attractive flower colors. To get a higher number of visits to a garden by bees so they can pollinate small yellow cucumber flowers, it’s a good idea to plant additional flowers they can see, such as borage to give them even more of a reason to stay and pollinate. Because bees are able to see ultraviolet colors, they are particularly drawn to yellow, orange, purple, blue and white flowers. Ask gardeners to identify bee-friendly borage, calendula, Black-eyed Susans, marigolds, salvia, alyssum, flowering anise hyssop, dandelions, and clover.

4. In addition to identifying flowers that are visibly attractive to pollinators, nectary length on blossoms. The proboscis (the insect’s nectar straw) differs in length between bees and butterflies, for example. Bees like flowers with short nectar spurs with easily accessible nectaries whereas butterflies and moths can be drawn to longer flowers like daylilies, nasturtium, and sage. Hummingbirds look for even longer nectar spurs such as fuschia, lilies, canna, and foxglove.

5. Scent can be an even stronger attraction than color, as a beacon for pollinators. While touring the garden, suggest that gardeners follow where their nose takes them. Stop to smell the scent of flowers like nasturtiums, marjoram/oregano flowers, and anise hyssop and discuss how the sweetness detectable in the scent tells the insect that the nectar will also be sweet.

Source: Environmental Education in the Community Garden materials were produced by the American Community Garden Association (ACGA). ACGA acknowledges EE Capacity, Cornell University, Civic Ecology Lab, United States Environmental Protection Agency, North American Association of Environmental Education, and Peterson Garden Project.

Interplanting for Pest Control

Interplanting is growing one kind of plant alongside a different kind of plant. Some plants attract helpful insects. Other plants confuse or repel insect pests. When these plants are interplanted, they can help protect your crops from insect pests.

Interplant to attract and shelter helpful insects

Most insects that eat insect pests also eat nectar and pollen from flowers. They have short mouth parts for chewing, rather than long tubes for sipping, so they need flowers with easy-to-reach nectar and pollen.

Flowers in the Aster family, such as marigolds and sunflowers, have wide, open flowers, so they are an excellent choice for attracting helpful insects.

Herbs like parsley, dill, and coriander have flat-topped clusters of small flowers. They also have strong fragrances that attract beneficial insects.

How to confuse or repel insect pests

Many insect pests attack only certain kinds of crops. They spread more quickly if a large area is planted with only the kind of crop they eat. If you interplant crops, it’s not as easy for insect pests to spread and cause damage.

A large cabbage patch presents a big target for cabbage white butterflies flying by. Also, lots of cabbages in one spot make it easier for the cabbage white butterflies to move from one cabbage to the next. The same number of cabbages scattered among other crops over a larger area is a much less obvious target.

Many gardeners interplant with herbs and flowers that have strong scents, which may confuse or repel insect pests looking for crops to feed on. Here are some combinations that many gardeners use.

• Marigolds among eggplants
• Nasturtiums among squash
• Basil among tomatoes
• Garlic among cabbage

Try this

CHECK ON INTERPLANTING FOR INSECT CONTROL IN THE GARDEN

What you need

• Paper and pencil
• Magnifying lens, if available
• Insect field guide, if available

What to do

1. Go to a garden to look for examples of interplanting for pest control. For example, try to find these flowers and herbs interplanted among crops: marigolds, zinnias, tansy, or other flowers in the Aster family; strong smelling herbs such as basil or dill; nasturtiums; and chives and garlic.
2. Look for insects around the interplanted flowers or herbs. Spend at least 5 to 10 minutes observing insects that you find. Use a magnifying lens to observe them more closely. Do they have mouth parts for sucking or chewing? Are they feeding on the nectar and pollen of the interplanted flowers and herbs? Draw pictures of the insects.
3. Try to identify the insects that you see. If possible, look them up in an insect field guide. Find out if they eat any insect pests.
4. Share your observations with other youth and adults.

Spotlight on research

How do you know what crops to combine when interplanting? Researchers at Cornell University in Ithaca, New York, tested a method for selecting vegetables suitable for interplanting. They listed all the vegetables commonly grown in New York State, and then listed all the pests common to each vegetable. They reasoned that interplanting vegetables that have different insect pests would make it harder for insect pests to find their food. They also thought that plots planted with a variety of vegetables would attract a greater variety of beneficial insects.

They planted five different kinds of plots:

1. Only squash;
2. Plants with different ways of growing and different pests (beets, broccoli, sweet corn, squash);
3. Plants with different ways of growing but with similar pests (sunflowers, cucumbers and squash);
4. Plants with similar ways of growing but different pests (eggplant, snap beans, squash).
5. Plants with similar ways of growing and similar pests (peppers, watermelon, squash, cucumbers).

The scientists sampled the insects by vacuuming each plot for one minute. They repeated this on five different days during the summer. Then they calculated the average number of beneficial and pest insects for each plot.

So far, their results show that interplanting of any vegetables increases the variety of beneficial insects. They will continue their research to test their hypothesis that combining crops having different pests and different growth habits will attract greater numbers and a greater variety of beneficial insects.

Source: Wright, M.G. and Hoffman, M.P. (2001) Selection of vegetables for intercropping as a pest management strategy. Organic Agriculture at Cornell. <http://www.organic.cornell.edu/research/ tsfsumms/organicpdfs/7intercrop.pdf>

Information from Garden Mosaics (www.gardenmosaics.org)

Garden Mosaics is funded by the National Science Foundation Informal Science Education program, and by the College of Agriculture and Life Sciences at Cornell University.

Plant Maintenance

What is plant maintenance?

Plant maintenance includes all the activities that need to be done to keep plants and soils healthy and productive. Over time, farmers get an idea of the timing of when tasks need to be done. When you are just starting out, the most important plant maintenance skill is observation. Observation means paying attention to plants and noticing when they are stressed or in need of care.

To be a good plant observer, don’t forget to:

• Look at the under sides of leaves and flowers. Insects and signs of disease some- times hide out of sight.
• Touch leaves, flowers and 
soils.

Touching when plants are healthy will help with knowing when a plant doesn’t feel healthy. Unhealthy plants might feel brittle, dry, or even slimy.

• Look at the soil. Healthy soil has the right amount of moisture, doesn’t smell bad, and doesn’t have algae or other things growing on the surface that make the texture slimy and steal water from plants. Unusual insect activity in or on soil can also be a sign that soils are unhealthy.
• Occasionally look at plant parts through a magnifying glass. Some diseases and pests can be better seen through a magnifying glass.

Soil Activities

• Tilling: The process of breaking up soil with the help of a machine (either a rototiller or a tractor).
• Double Digging: The process of breaking up soil by hand, using a shovel.
• Cultivating: The process of loosening the soil around existing plantings to cut down on weeds and add air and water space to the soil.
• Composting: The process of breaking down organic materials to create a soil amendment and fertilizer.
• Fertilizing: The process of adding nutrients to the soil.

Seeding Activities

• Starting Seeds: Some seeds need to be grown indoors be- fore they are put into the ground as plants.
• Direct Sowing: Other seeds can be planted directly in the ground.
• Thinning: The process of re- moving seedlings that are planted too closely together to give room to other seedlings. This can be done with seeds started indoors or seeds that are direct sown.
• Saving Seed: The process of letting some plants form seeds that can be collected and saved to be planted again the following year.
• Storing Seed: When storing seeds over the winter, it is important to keep them dry and at a cool temperature. Stored seeds also need to be kept out of reach from pests such as mice.

Planting Activities

• Hardening Off: The process of letting plants that were grown in- doors adapt to being outside before being transplanted. Plants in pots are usually left outdoors for a few hours every day for about one week before planting.
• Planting/Transplanting: Planting or transplanting is the process of moving a plant from one location to another. Usually the plant is moved from a pot to the ground, but some- times plants are dug from the ground and moved to another location in the ground.
• Succession Planting: The process of harvesting crops quickly and planting in the same spot after harvest. Succession planting takes place over one season.
• Companion Planting: The process of planting different crops near each other to help with plant nutrition, insect and disease prevention, pollination and vertical growth. 
Pest and Disease Activities
• Cleaning Up Plant Debris: The process of removing dead plant material from plants and from the ground.
• Removing Infected Plants: The process of removing an entire plant that has a disease or a bad insect infestation.
• Beneficial Insect Release: The process of releasing beneficial in- sects that will eat unwanted pests. 
Growing Activities
• Bolting: Bolting is what happens to a plant when it starts to develop flowers and the edible parts of the plant become bitter. Usually, the entire plant is removed at this point.
• Pruning: The process of removing parts of a plant for the health of the plant, for the visual appearance of the plant, or for functional reasons (for example, the plant is growing over a pathway).
• Pinching Back: A type of pruning that is done to young plants to help keep the plant small and encourage branching.
• Dead Heading: Removing dead flower heads so that the plant puts more energy into creating new growth and flowers.
• Staking: The process of supporting a plant so that it doesn’t grow on the ground and crowd other plants.
• Blanching: A process of growing certain vegetables in darkness to make them more white. This is usually done with cauliflower and endive.
• Harvesting: The process of gathering crops that are ready to eat.

Source: Urban Botanical University/Denver Botanic Garden
Unit 2 Chapter 7
Author: M. Bumgarner 

Watering Garden Plants

To water or not to water?

In most areas, rain alone does not meet all the water needs of garden plants. You need to water the garden.

You need to add enough water so that it seeps all the way down to the plant roots. If you just water the soil surface, the roots will grow close to the surface and then the plants will wilt more quickly.

Watering methods

1. A watering can and hose are useful for small gardens.
2. Sprinklers are cheap and convenient, but they waste a lot of water to evaporation, especially on hot, windy days.
3. A drip or trickle irrigation system applies water directly to the area in the soil where roots are growing.
4. A soaker hose is a plastic or canvas hose with holes all along its length. It is placed along one side of plants or underneath mulch. Water seeps out slowly.

Many farmers in hot, dry places use drip or trickle irrigation. Little water is lost to evaporation or run-off when you use the drip or soaker hose methods because the water goes into the ground near the plant. The gentle stream of water causes little or no compaction of the soil.

Saving water in the garden

Make the most of available water in the garden.

Collect rain water from roof-tops in rain barrels. Keep the rain barrel covered to prevent mosquitoes from breeding.

Water during early morning. At this time temperatures are cooler and it is less windy, so there is less evaporation.

Add organic matter to the soil. It holds the water, which then can be used by plants.

In most areas, rain alone does not meet all the water needs of garden plants. You need to water the garden.

Cover the soil with mulch, which smothers weeds and allows water to seep slowly into the soil. A mulch cover also reduces evaporation of water from the soil.

Try this: Drip irrigation for garden plants

What you need

• plastic one-gallon milk jugs
• clothespin with spring
• candle
• matches
• pin

What to do

1. Light the candle. Use the clothespin to hold the pin. Place the sharp end of the pin in the candle flame until it is hot. Use the hot pin to melt about 8 to 10 small holes in the bottom of the milk jug. CAUTION: Do this only under the supervision of an adult.
2. Put some water in the jug to make sure the water will slowly drip out of it.
3. Bury the milk jug between widely spaced plants in the garden, such as tomatoes, peppers, eggplants, or squash. The bottom 15 cm of the jug should be buried (see picture).
4. Fill the jug with water every few days during dry spells.
5. Observe how well the plants near the jug grow, compared to plants without drip irrigation.

Spotlight on research

Dream up a watering invention Can you think of a creative irrigation idea for gardeners and small farmers? Each year the World Bank and the United Nations sponsor a contest to promote irrigation systems for small farmers and gardeners. The irrigation systems must be affordable, creative, easy to operate, and useful in many areas around the world. One of the contest winners was a “Dream Kit” for drip irrigation, designed by Stephen Ngigi at the University of Nairobi in Kenya. The Dream Kit consists of a bucket mounted on a wooden stand above the ground. The bucket is connected to pipes with tiny holes in them, through which water drips out along a row of crops. In dry areas, the bucket is filled twice a day. Thanks to the Dream Kit, small farmers in Kenya have been able to grow much needed vegetables to sell and to eat. The kit can easily be put together and repaired by farmers, and costs only U.S. $15.00. Within three months, farmers can make four times this much by selling crops that would otherwise be difficult to grow. The Dream Kit truly deserves its name!

Source: Keller, J. (2002). Contest for Innovative Irrigation Ideas and Technologies for Smallholders. World Bank, Washington D.C. <lnweb18.worldbank.org/…/$FILEtopentrantsI&Dcontest.pdf>

Information from Garden Mosaics (www.gardenmosaics.org)

Garden Mosaics is funded by the National Science Foundation Informal Science Education program, and by the College of Agriculture and Life Sciences at Cornell University.

Harvesting

When to harvest

Earlier, maturity dates for each vegetables were listed (see Calendars and Scheduling). The number of days to maturity for each vegetable is added to the date the vegetable was sown. The date you come up with is when you can expect to harvest. For example:

Beets
Date Sown: April 10
Days to Maturity: 55-65 days Harvest Date: June 5 – 15

Remember that some vegetable varieties are determinants, and will have a single, large harvest. Other vegetable varieties are indeterminant and they will need to be harvested regularly.

By planning ahead and knowing when to expect a crop to be ready, you can:

• Plan work days ahead of time.
• Prepare for cleaning and/or storage of vegetables.
• Maximize the harvest and create less waste.
• Let shareholders (or purchasers) know when to expect certain vegetables.
• Even though crops are generally ready around their maturity date, it is still very important to check for ripeness before harvesting.
• Be sure to read seed packets and take note of harvesting sizes for individual vegetables and varieties.
• During harvest season, check for ripeness daily; crops can mature overnight depending on the weather. This can be done when watering and working on the farm.
• Pick vegetables as soon as they are ripe. The produce will be at its maximum flavor, 
texture and color, and picking encourages the plant to produce more vegetables.
• If vegetables are harvested early or late they can still be used in sauces or for pickling, but they will not have as nice a texture and flavor if they are eaten raw.
• Be careful not to harvest rotten vegetables. 
Placing rotten vegetables in a bin with other harvested vegetables will cause the rest of the vegetables to ripen faster than normal.

The first step in harvesting is preparation. Make sure that:

• There are enough harvest bins/ baskets and that they are clean
• Harvesting tools are cleaned be- fore the beginning of each harvest
• There is enough room in the cooler or other storage areas to hold the harvest
• Harvest only ripe vegetables and make sure that there is enough time to clean and process the food the same day that it is harvested. The next section will cover cleaning for specific vegetables. Once vegetables are cleaned, they need to be sorted by their usage (storing, selling, canning) and stored as soon as possible.
• The following are harvesting tips for specific vegetables:

Broccoli, Cauliflower, Cabbage

In Colorado, broccoli, cauliflower and cabbage are cool season crops because they are very quick to bolt in the warmer months. Broccoli crowns are usually harvested small (to avoid bolting), but crowns can be harvested from the same plant for 6-8 weeks. Cauliflower is usually harvested as one head, and it is much slower to develop. To avoid ruining the head, cauliflower leaves are often tied together in a process called blanching. Heads of cabbage are also slow to form and usually one plant only yields one head of cabbage. All three vegetables can be harvested with a harvest knife by cutting the desired crop from the rest of the plant. Usually, cauliflower and cabbage plants are fully re- moved from the ground and then the vegetable is cut from the rest of the plant.

Cucumbers

Check the seed packet to see how large the variety should be. 
Cucumbers can be picked smaller to be used for pickling, but cucumbers that have gotten too large have larger seeds and lose their flavor.

Eggplant

Eggplants taste better when they are still small; eggplants that are left on the plant too long take on a bitter taste. When an eggplant is ready to harvest, the skin goes from dull to shiny. Eggplants should be cut from the plant instead of pulled.

Green Beans

Pick bean pods when they are little smaller than their maxi- mum size. Larger beans will have tough pods and hard beans. To avoid spreading plant diseases, don’t harvest beans when they are wet; this includes morning dew. Harvest beans regularly to encourage the plant to produce more beans.

Herbs

Pinch and/or cut back regularly. Pinching makes a bushier plant that is producing more leaves. Pinching also keeps the plant from flowering; once an herb flowers, the leaves can taste bitter.

Lettuce

It is important to pick lettuce before hot weather sets in to avoid bolting. With leaf lettuce, cut about a third to two-thirds of the leaves at a time when leaves are no more than 5 inches long. The same patch of leaf lettuce can be harvest every 5-7 days using this method until it gets too warm. Head lettuce is left alone until it forms a large enough head to be harvested. The head is removed from the ground en- tirely, and the roots are cut off.

Melons (Cantaloupe, muskmelon and honeydew)

This is one of the hardest vegetables to determine the time it is ripe. A ripe cantaloupe or muskmelon will turn from green to brown underneath the netting on the rind. A honeydew will go from feeling hairy to feeling smooth. Fruit should be cut from the vine rather than broken to prevent plant disease. Before eating, fruit should be stored for a few days to further ripen.

Peas

Peas are considered ripe when they taste their best. For shelling peas, open a test pod and taste the peas. They should be round, but still tender. For snow and sugar snap peas, taste the entire pod. The pod should be crisp and crunchy, but not stringy; the peas should be developed but nowhere near round.

Peppers

Most peppers, regardless of variety, can be harvested when they are a good size and they are green. However, a lot of pepper varieties will turn a different color if left on the plant and the flavor will start to deepen. With hot peppers, the longer they are left on the vine, the hotter they become. Peppers should be cut (with scissors or pruners) from the plant instead of being pulled off.

Root Vegetables

Know your expected maturity date. Around that time, pull a few test vegetables out of the ground to check for size. Root vegetables are more tender when eaten young, but they can be left in the ground to produce larger vegetables. Larger vegetables will be tougher and might require cooking. Root vegetables can even be stored in the ground throughout the winter.

Spinach

Spinach prefers short days and cool temperatures; when grown in the summer, it bolts very quickly. One to two thirds of all the leaves on a spin- ach plant can be harvested at one time. Much like leaf lettuce, the same plant can be harvested every 5 to 7 days. Spinach leaves are best when they are no more than about 3-4” long and still have a mostly round tip; once the leaves become more triangle shaped, the spinach has become tough and bitter.

Sweet Corn

Corn kernels begin to lose their flavor immediately after harvest, so it is important to wait to pick corn until it is going to be used. Corn is ready to be harvested when the kernels feel full and round, the silk at the top of the ear has started to dry out, and a squished kernel produces a milky sap.

Tomatoes

Generally, a tomato is ready for harvest when it releases from the stem without having to be cut. Col- or is a difficult test, because color can be dramatically different between varieties. If tomatoes are harvested too early, they can be stored for about a week to increase the ripeness.

Watermelon

Watermelon is ready to be harvested when the spot beneath the melon, where it sits on the ground, turns yellow. The rind will also be tougher, which can be tested with a fingernail.

Source: Urban Botanical University/Denver Botanic Garden
Unit 3 Chapter 6
Author: J. Casault

Crop Rotation

Mix it up! Crop rotation, intercropping & succession

Just as we are healthiest when eating a widely varied diet, organisms in the soil also benefit from a diverse diet of organic material. Plant nutrients come from minerals made available by decaying plants and animals, but roots also exchange nutrients and electrical charges with microorganisms in the soil. Different roots provide different nutrients to the microorganisms, and vice versa. All vegetables have specific nutrient and soil requirements, so by grouping crops with similar needs together and rotating if possible every year, the soil maintains the ability to replenish lost minerals and efficiently support each crop.

Crop rotation (cycling different plants and plant families in the same area) introduces different plant exudates and biological relationships. Because some plants use more of certain nutrients and some plants leave nutrients in the soil after they die (such as nitrogen-fixing legumes), rotating crops and planting a variety of plant families in a bed helps support diverse forms of microbial life. The diverse microbial community nurtures balance in the food web so that one kind of organism or nutrient doesn’t get to powerful and throw off the system.

Crop rotation also supports plants’ ability to fend off disease and pests by nurturing a more robust and well-nourished plant. Disease spores in the soil can easily be moved from a crop’s previous location to the new location, however, the access to different microbial life and nutrients ideally contributes to the overall health and general immunity of the plant.

Succession planting is a practice of replacing short-season crops such as lettuce with new crops in the same location. Intercropping involves planting a short season crop at the same time as a long season crop, and harvesting the first crop before the long season crop (such as tomatoes) reach full size and require more space and nutrients.

Both succession planting and intercropping can provide multiple cycles of nutrient and microbe benefits similar to annual crop rotation during a single growing season. Combined with techniques that add organic matter to well-structured soil, succession planting and intercropping can help community gardeners increase productivity in their limited space while improving overall soil health.

Lesson plan: Plan for variety

OBJECTIVE: Teach gardeners how to adapt their garden plans to account for crop rotation, intercropping, and succession planting within the challenges of limited space in a plot.

Demonstrate several garden planning techniques from hand written plans to online square foot gardening planners, and options for determinine season length and short/long season crops.

MATERIALS NEEDED:

• Garden planning materials for each individual gardener’s spring planting plan including paper, pencils, seed packets (for planting and “days to maturity” instructions).
• Optional computer and wireless access for using online garden planning tools like the square foot garden planner at www.gardeners.com

Activities:

1. Ask gardeners to bring their spring garden plan with them or begin the lesson by reviewing a list of vegetable and herb options for spring planting.

2. Suggest resources such as www.motherearthnews.com or www. farmersalmanac.com for determining average first and last frost dates. Review “cool season/warm season” and “days to maturity” information on seed packets. Explain how this information reveals length of growing season and days that gardeners can divide into mini-seasons for succession planting, intercropping and minimal crop rotation. Days to maturity will also be impacted by days getting longer or getting shorter as the sun moves in position in the sky over the summer. Lettuce planted in the spring may take 45 days while the same variety planted in fall may take 55.

3. Discuss how warm weather and long “days to maturity” length crops such as tomatoes, okra, cucumbers, peppers, and eggplant can be added later amid stands of cool weather, short “days to maturity” lettuce or spring peas with proper planning.

4. Review vegetable families and their feeding needs: root vegetables and phosphorous; the nightshade family’s need for nitrogen and potassium; the nitrogen-fixing capacity of legumes (beans and peas); relationship between different brassicas and cucurbit plants. These feeding habits influence nutrients left in the soil as well as microbial life.

5. Ask gardeners to develop three years of garden plans or create separate plans for spring, mid-summer, and fall planting. Discuss the complications involved in making these planting decisions (such as the path of light in the garden, placement of trellises, space limitations).

Plan for variety

6. Encourage gardeners to be open to experimenting with rotation as it is possible in the limited space of community gardens. Balancing the benefits of rotation and intercropping with the necessities of community gardens by emphasizing that other good gardening techniques also encourage diversity in the soil. While it would be best not to plant tomatoes in the same exact place each year, an awareness of the soil’s needs will help gardeners make informed decisions and necessary amendments as they plan their gardens throughout the years.

7. Introduce gardeners to vegetable families as guides for crop rotation. Explain that rotating crops in larger groups based upon the part of a plant we eat provides an easy to remember alternative guide. Categories include: legumes (beans, peas); leaves (lettuce, greens, spinach, herbs); roots (onions, beets, carrots, turnips); and fruits (tomatoes, peppers, cucumbers). In a raised bed plot, crop rotation can be broken into general groups and areas in the garden annually, since traditional crop rotation and field change is not possible.

Source: Environmental Education in the Community Garden materials were produced by the American Community Garden Association (ACGA). ACGA acknowledges EE Capacity, Cornell University, Civic Ecology Lab, United States Environmental Protection Agency, North American Association of Environmental Education, and Peterson Garden Project.