Creating and Maintaining an Organic Vegetable Garden – Part Two

Estimated reading time: 22 minutes

This is the second part of a two-part series on creating and maintaining an organic vegetable garden. The focus of the first part was soil health and how to maintain healthy soil. In Part Two, we get down to the nitty-gritty of managing an organic garden and focus on the following topics:

• Seeds
• Tillage
• Irrigation
• Fertilizers
• Insect Management
• Disease Management

From my writing desk, I have a perfect view of our backyard vegetable garden. Not a day goes by when I don’t think about the topics list above. Because a vegetable garden is so dynamic and ever-changing, these topics constantly come into play. With that, let’s start with Part Two of creating and maintaining an organic vegetable garden.

Organic Seeds

To understand and appreciate organic seed, we must first understand non-organic seed. Most home gardeners plant a seed for the resulting harvest and consumption of vegetables, fruit, herbs, and/or flowers. However, on seed farms, farmers cultivate plants specifically for seed production instead of edible food products. On non-organic farms, synthetic chemicals and pesticides are used on the plants that produce the seed. Not only that but current regulations allow higher percentages of chemicals to be applied on plants that are grown for seed production as opposed to consumption. Because plants being grown for seed are in the ground longer, therefore, more chemicals applied.

On the other hand, organic seed farms with a certification from the US Department of Agriculture (USDA) must abide by the regulations of the National Organic Program (NOP). We know from Part One, that synthetic chemicals and pesticides are not allowed under this program. In addition, organic farms must use organic seeds to meet the requirements under the USDA National Organic Program.

Ok, so what does this all mean? Well, by choosing organic seed you are not contributing to pollution caused by conventional seed production due to the use of chemicals. In addition, you are starting your plants from seeds that do not have any chemical treatment. Therefore, a key to creating and maintaining an organic garden is the use of organic seed.

Seed Descriptions

To complete our discussion on seed, we need to understand the various descriptors found on seed packages. Because these descriptions can be confusing, a definition of common terms can be found below.

Open Pollinated Seed

Hybrid Seed

Heirloom Seed

Organic Seed

Biodynamic Seed

Tillage

Tillage has been such a confusing topic for me personally. As I read about home gardeners adhering to no-till practices, I wonder what this really means. This section will discuss tilling practices that are good for soil health in creating and maintaining an organic vegetable garden.

First, let me start by saying I like the term ‘low till’ as opposed to ‘no till’. If you follow the soil health practices in Part One, there will always be a need to incorporate manures, compost, and cover crops into the soil via some low till method.

Now, let’s back up and define tillage and degrees of tillage in the context of a home garden. When applied in an agricultural sense, tillage is the process of agitating the soil by some mechanical means. Mechanical can be via hand tools such as broadforks, rakes, hoeing, or shoveling. In addition, there are methods such as rototilling and plowing.

What is the impact of tillage on soil health? Well, the soil is filled with a dynamic array of microorganisms that include both bacteria and fungi. Among other things, these microorganisms control plant nutrient availability, nitrogen cycling, and organic matter decomposition. Too much tillage can weaken the ability of these microorganisms to do their work. The bottom line, your soil will be more productive the less we disturb these microorganisms. Therefore, no or low tillage is better for soil health. 

Types of soil tillage

In conventional tillage, there are three types:

1. Primary – Primary tillage is deep tillage that mixes the first 6 inches to 2 feet of soil. This type of tillage can be used to incorporate organic matter, cover crops, and aerate the soil. For the home gardener, the tools used include a spade, pitchfork or a broad fork.
2. Secondary – This is shallow tillage applied to the first 3-6 inches of soil to produce a seed or transplant bed. The goal is to reduce the soil particle size thus creating a smooth bed. A rake is an example of a tool that a home gardener would use.
3. Cultivation Tillage – This is a shallow form of tillage used post-planting to loosen the soil or remove unwanted weeds growing around a cultivated crop. Hand weeding and hoes are examples of what a home gardener would use.

In the past, primary tillage was a common method for creating new in-ground garden beds. Today, there are no-till practices such as ‘lasagna gardening’ that eliminates the need for primary tillage. Lasagna gardening is a no-dig method to create a new garden bed. 

Lasagna Gardening

This method, also known as sheet composting, is a method where the soil is left undisturbed under layers of mulch. Lasagna gardening takes time because the composting process is slow. Thus, give yourself time to plan. For our ‘lasagna’ garden beds, the process began in the fall and was complete the following spring. First, we marked out the area for the new beds. Next, a layer of cardboard was laid directly over the grass. From there we spread peat moss, composted cow manure, topsoil, and a layer of wood chips. In the spring, we had an amazing garden bed into which we directly planted.

Tillage considerations

The key to maintaining a no-till or low till garden is to cover the soil at all times. This includes planting your primary crops, using cover crops, or covering the soil with organic mulch such as leaves or straw. Tilling is also dependent upon the type of soil you have. It is generally easier to apply a low till method to sandy soils than to clay soils.

Our vegetable garden in NJ has heavy clay soil. While I practice cover cropping, I still find it helpful to perform primary tillage using a broadfork once a year. I use the broadfork to aerate and loosen the first 6 inches of soil prior to creating a smooth garden bed. For our soil, this process improves drainage, increases root depth, thus making nutrients more accessible to the roots.

At the end of the day, do what is best for your garden and soil type. Studies have shown that a less tilled garden is better for both allowing microorganisms to do their work and for sequestering carbon in the soil. For new garden beds, I highly encourage the lasagna method.

Irrigation

Irrigation is a universal topic whether you are creating and maintaining an organic vegetable garden or conventional garden. I cover it here because it is important. Have you ever stopped to think about what watering the garden accomplishes? We know plants need water, but why? Here is what watering does for plants:

• Sustains the biological and chemical activity that occurs in soil. Thus, more optimal growing conditions are maintained.
• Irrigation dissolves the nutrients in the soil allowing plants to uptake.
• Provide physical support for the plant.
• Maintains an optimal temperature within the plant.
• Reduces plant stress thus enabling the plant to fight off disease and pests.

Watering Frequency

So, what impacts watering frequency? Well, there are several factors including:

• The climate includes air temperature, precipitation, humidity, and high wind. High air temperatures and wind will increase the need for watering. Precipitation and humidity will decrease the need.
• Soil type. Sandy soils drain quickly and do not hold water. Silt soils drain slowly and hold water well. Clay soil drains very slowly and holds water tight. Loam soils (ideal combination of sand, silt, clay, and organic matter) drain well and hold water.  
• Stage of crop development and crop type
  • Water-loving crops such as celery require a consistent supply of water.
  • Drought-tolerant crops (certain tomato and winter squash varieties) require little to no additional water.
  • Crop stage of development. Water is generally more important at the following stages:
    •  Flowering
    • When fruit is first being set
    • At the seedling stage
    • When fruit is ripening
  • Crops such as onions and garlic require a reduction in watering as they reach maturation.

How much water does a vegetable garden need?

A general rule to follow is that sandy soils need ½ inch of water a week while clay soils need 1 inch of water per week. However, I find it difficult to think of watering in terms of inches. Therefore, let’s convert inches to gallons. We will use my garden as an example.

• The total square footage of my garden is 800 square feet. However, that includes the paths between the garden beds. Within the 800 square feet, I have 14 beds of various sizes. The total square footage of these beds is 360 square feet (summing up the length times width of each bed).
• For a 100 square foot area, 1 inch of rain amounts to 62 gallons of water/week. Yes, that’s a lot of water. A 4 x 8-foot bed, which is 32 square feet, requires approximately 20 gallons of water/week.
• For my garden to receive 1 inch of water per week, here is the calculation.

360 (Sq ft of my garden)/100 = 3.6 * 62 = 223.2 gallons of water/week                                           

How long does your irrigation system need to run?

Now you know how much water you need for your garden. The next question is how long to run the water supply?

Hand Watering

In this example, we will assume hand watering with a garden hose.

• First, you can purchase a ‘water meter’ that attaches to your hose. This meter will measure the number of gallons of water deployed over a period. In this case, record the time you begin and end watering. Next, check the water meter for the number of gallons deployed. Based on the number of minutes and water deployed, you can figure out how long hand watering will take to achieve your watering goal.
• Second, if you don’t have a water meter, you can figure out gallons consumed. Get a container, such as a 5-gallon container. Fill the container with water and record the time it took to fill the container. Let’s say it took 3 minutes to fill the 5-gallon container. Therefore, you know that 5 gallons of water are deployed in 3 minutes. In our example, to deploy 223 gallons of water here is the calculation:
  •   223 (Water requirement)  / 5 (bucket size) = 44.6
  • 44.6 * 3 (minutes to fill a 5 gallon bucket) = 134 minutes
• In conclusion, it would take 134 minutes to get 1-inch of water coverage in my garden via the hand watering method. Assuming there is no rain, you might break this watering process up across 3 days and water approximately 45 minutes per day (134/3 = 45).

Drip Irrigation

In this example, we will assume watering with drip irrigation.

• Most irrigation systems will define the gpm (gallons per minute) of water deployed. This is also known as the systems output rating. To find the gpm, either check the packaging materials or the manufactures website.
• Back to the example of my garden. Let’s assume that the drip irrigation system I purchase has a gpm of .45 gallons per minute.
  • 223 (Water requirement)  / .45(drip system gpm) = 495 minutes or 8 hours
• In conclusion, it would take 495 minutes to get 1-inch of water coverage in my garden via the drip irrigation method. Assuming there is no rain, you might break this watering process up across 7 days and water approximately 70 minutes per day (495/7=70 minutes/per day).

When is the best time to water?

Below are watering guidelines:

• Water in the morning when possible. This gives the sun time to dry up the moisture that remains on the plant leaves. Disease problems are more likely when water sits on wet leaf surfaces overnight.
• Use a rain gauge in the garden to measure the natural rainfall as this will advise whether you need to adjust your irrigation schedule. For example, if you receive one inch of rain in a single day, watering will not be necessary for another week.
• It’s better to water for longer periods of time to allow water to penetrate down to the roots. This will encourage roots to grow deeper into the ground.
• If hand watering, aim the water at the base of the plant. Try to avoid watering the leaves.
• Soaker hoses and drip irrigation systems are best in a vegetable garden. They deliver water slowly and directly at the root system.

Fertilizers

The approach for managing plant nutrients in creating and maintaining an organic vegetable garden is different from a conventional garden. In an organic garden, the strategy is to build nutrient-rich soil via adding organic matter such as composted manure, compost, and cover crops. In Part One of creating and maintaining an organic garden, the topic of soil health is discussed in depth.

However, even in an organic garden, it is usually necessary to supply supplemental nutrients. Plants need both macro and micronutrients. Good soil should contain the following three macro elements:

• Nitrogen (N) – provides sturdy green growth and is a major constituent of chlorophyll
• Phosphorus (P) – necessary for the development of flowers and resistance to disease
• Potassium (K) – affects root and leaf growth and is especially important for root crops (carrots, beets, onions)

Fertilizers contain three numbers on the label such as 5-10-5.  This implies the percentage of N, P, and K.  In a 5-10-5 fertilizer, there is 5% nitrogen, 10% phosphorus and 5% potassium. A soil test will let you know whether your soil is deficient in any of the above nutrients except nitrogen. Soil tests cannot measure nitrogen because it is too dynamic.

Types of organic fertilizers

Here are types of organic fertilizers that contain macro nutrients:

• Rock Phosphate – provides 25% of phosphorus and 25% calcium
• Bone meal – 2% nitrogen, 15% phosphorus, and 20% calcium
• Fish emulsion – 4% nitrogen, 2% phosphorus, 2% potassium, 1% calcium
• Blood meal – 13% nitrogen
• Epson Salts – 10% magnesium
• Greensand – 9% potassium

Calcium and magnesium are considered micronutrients. The difference between macro and micronutrients is that plants need higher quantities of macro nutrients while needing only minute supplies of micronutrients.

Each vegetable crop is different regarding nutrient requirements. In addition, nutrient needs change as the plant grows. While nitrogen may be needed to encourage new growth, when a plant produces fruit, phosphorous may be needed. Therefore, it’s best to research each crop to understand the nutrient needs.

Pest Management

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I have come to learn that prevention and growing healthy plants is the best approach to managing pests in creating and maintaining an organic vegetable garden. There is a worldwide standard for managing garden pests (including disease) called Integrated Pest Management (IPM). I like the framework because it guides you through a thoughtful process to understand the underlying cause.  Finally, the goal is not to eliminate all pests, but rather to manage pests at an acceptable level.         

One aspect of IPM is prevention. There are two key practices you can follow:      

• Understand your environment and your plant – put the right cultural controls in place from the start. For example, plant in the right place, at the right time, with the right spacing, sun, water, soil, and nutrients. Strong plants resist pests and disease. Of all the cultural controls, having good soil amended with organic matter (like compost) will give your plants the best possible start and opportunity to grow.
• Be observant – Make a habit to routinely walk around your garden to spot problems early. It is especially important to look at the leaves of plants and turn them over. Many pests will live on the underside of leaves.

Options for pest management

Here are four options to manage pests in the garden. When considering options, chemical (organic or synthetic) should always be the last option.

1. Physical control 

Physical control involves preventing access to your plant or physically removing pests from the plant. Examples include:

• Hand removal of insects. For example, picking off beetles.
• Floating row covers are a great method to prevent insects from reaching plants. What is a floating row cover? It’s a type of material that you place over plants. For example, to protect against the cabbage worm, I cover all brassica crops (kale, cabbage, broccoli) with a mesh fabric row cover. This prevents the cabbage moth from laying eggs on the plants.
• Lay down black plastic for weed suppression.

2. Genetic control 

Each year, there are more varieties of plants that are bred to be resistant to certain pests and diseases. When purchasing seeds, check the label to understand if the seeds are resistant to pests or diseases. Disease resistent varieties are usually hybrid seeds.

3. Biological control *

Sometimes you will read about attracting ‘beneficial’ insects to your garden. A few examples of beneficial insects include ladybugs (feed on aphids and spider mites), dragonflies (feed on mosquitoes and flies), praying mantis (feed on flies and grasshoppers), and parasitic wasps (feed on aphids, flies, caterpillars). To attract beneficial insects, plant native plants in and around your garden.

4. Chemical control 

This should be your last option. However, there are organic chemical controls to consider. First, identify the pest. Second, determine the extent of the pest damage. Chemical controls should only be used when there is a pest problem that cannot be controlled with other methods. When resorting to chemical control, thoroughly read the label on the product. The label will indicate insects that are controlled, the proper application technique, the application rate/amount, and the toxicity.

• Pyrethrum/pyrethrin are derived from chrysanthemums. They are one of the oldest and most widely used botanical insecticides. These can be used on a wide variety of insects and affects the insect nervous system.
• Neem is derived from the seeds of a neem tree which is native to India. Effective on a wide variety of insects but a slow-acting treatment.
• Horticultural Oils are effective on a wide variety of insects but can only be used on woody plants.
• Bt (Bacillus thuringiensis) is a naturally occurring bacterium found in some soils. It produces proteins that are toxic to insects. Bt is highly effective against caterpillars.
• Insecticidal soaps are very safe and effective at controlling several insects. They kill by suffocation and most small, soft-bodied insects are susceptible to soaps (aphids, mealybugs, thrips, scale crawlers, and spider mites)

In summary

Look for the Organic Label or OMRI label on any chemical control that you purchase for your organic garden. In addition, always read the label for directions on when and how much to apply.

Disease Management

 As is the case for pest management, the key to disease management in creating and maintaining an organic vegetable garden is prevention. Use the following strategies to manage disease in an organic vegetable garden.            

1 Purchase disease-resistant seeds or transplants

There are many hybrid plants that have been specifically bred to resist disease. This does not necessarily mean that the plant will not get the disease, but the impact will not be as great. Seed packages will list the disease resistance.

2. Practice Crop Rotation

Crop rotation is the practice of moving vegetables around your garden each year (e.g., not planting your lettuce in the same place each year). Why is this important? Rotating crops does two key things, first it interrupts the insect and disease cycle that may have disturbed your vegetables in the prior year and second it allows the soil to regenerate from the nutrients that the prior crop took out of the soil.

3. Follow guidelines for plant spacing

Air circulation and light intensity are improved with proper spacing, thus discouraging disease from developing. 

4. Remove and destroy any plant showing signs of severe disease symptoms.

If left in the garden, additional plants can be impacted by the same disease. 

5. Use Drip Irrigation

Because drip irrigation concentrates water at the base of the plant (instead of the leaves), disease is less likely to occur. 

6. Mulch

Mulching will control disease by reducing contact between the plant and soil. Mulches include straw, hay, wood chips, and leaves.

7. Maintain good garden hygiene and sanitation

Clean up old plant debris and sanitize garden tools and contains after use. 

A word about fungicides

Organic fungicides can be helpful to prevent the development of disease. Thus, apply fungicides prior to evidence of disease. Here is a link to a good resource for more information about organic fungicides. Look for the Organic Label or OMRI label on any chemical control that you purchase for your organic garden.

Additional Information

You may find these posts to be of interest in creating and maintaining an organic vegetable garden.

• Creating and maintaining an organic vegetable garden – Part One
• How to use floating row cover in your organic garden
• Managing garden pests with an integrated approach
• Companion planting for pest management in the vegetable garden
• Install a solar powered fence to keep groundhogs out of the garden
• Getting started with seeds, 4 secrets for successful seed starting
• A charming small-scale market garden: Brookstone Garden
  

References

University of Missouri Extension – Organic Vegetable Gardening Techniques

University of Minnesota Extension – Watering your vegetable garden

Texas A&M Agrilife Extension – Watering your vegetables

UNH Extension – Low and No Till Gardening

UC Master Gardeners – Lasagna Gardening