BMPs for Idaho Gardens

Idaho's Water
Over 90 percent of the drinking water consumed in Idaho is supplied by groundwater. This resource is vital to homeowners and industry.

Recent surveys in Idaho have found trace amounts of chemicals--nitrate--and, in some cases, pesticides in some of Idaho's drinking water. Nitrates and pesticides can get into groundwater through agricultural, industrial, and homeowner uses as well as spills and improper disposal. Contaminated water is difficult and expensive to manage once it becomes dispersed underground.

Your Garden Ecosystem
Think of your garden as a self-perpetuating ecosystem, a grouping of plants, animals, and other organisms interacting with each other and their environment.

Look at your complex garden ecosystem. You will see ornamental plants, fruit trees, vegetables, and weeds, but there is much more. Your garden is also visited by animals, insects, and birds. Your soil is teeming with worms, insects, fungi, and microorganisms such as bacteria.

All ecosystems have three basic interacting categories of organisms:

1. Producers
2. Consumers
3. Decomposers

Producers. Green plants convert sunlight, carbon dioxide, and water into energy for plant growth through a process called photosynthesis. All energy needed to make your garden ecosystem function smoothly is created by the producers.

Consumers. These are the organisms that feed on live plant or animal material. Some consumers are animals or insects that eat the green plants in your garden, and others are animals that eat other animals in your garden.

Decomposers. Dead plant and animal material are used by decomposer organisms as an energy source. Some of these decomposers we can see with the naked eye--like earthworms and some insects. Other decomposers are microscopic in size. Decomposers recycle nutrients in your garden ecosystem.

Ecosystem Balance and Imbalance
A healthy garden ecosystem will reach a balance between producers, consumers, and decomposers. With minimal disturbance your garden ecosystem is balanced and all nutrients are recycled.

Increasing inputs or outputs may imbalance your garden ecosystem. Inputs by gardeners like fertilizers or pesticides can throw the garden ecosystem out of balance. In addition, outputs such as removing flowers, vegetables, or leaves from your garden depletes your ecosystem of nutrients. The more inputs and outputs, the greater the overall imbalance of the system.

What inputs can throw your garden ecosystem out of balance?

1. Pesticides
2. Fertilizers
3. Water

To protect the environment and water quality you should use best management practices (BMPs), which are defined as implemented strategies that eliminate or minimize environmental pollution. BMPs are designed to be compatible with good, sound garden management. BMPs can protect the environment without compromising your garden ecosystem.

Pest Management BMPs
Pesticide use in your garden ecosystem must be done with care. Keep in mind that pesticides may kill beneficial insects or plants along with the insect pests or weeds. These beneficial organisms help reduce pressure from other pests and keep your garden ecosystem healthy.

Pest management BMPs you should implement in your garden include:

1. Create a garden with diversity.
• Plant a combination of different types of plants in your garden to create a balanced ecosystem.
• Annuals and perennials.
• Woody and herbaceous.
• Evergreen and deciduous.
• Tall trees and shrubs, short trees and shrubs, short plants, and ground cover.
• Rotate all plants to outsmart potential pests and minimize the threat of soil borne diseases.
2. Know what is in your garden!
• Identify your garden plants. Learn what growth conditions favor their health.
• Positively identify your insect pests.
• Positively identify your weed pests.
3. Maximize conditions for healthy plant growth.
• Space plants to allow ample root and top growth at maturity.
• Group plants according to water needs and water appropriately.
• Choose plants suited to your climate.
• Site plants according to light requirements--sun or shade.
• Choose plants resistant to diseases and insects common to the area.
4. Protect beneficial insects.
• Learn to recognize the eggs and larvae of beneficial insects so not to harm them.
• Develop garden habitats to ensure a positive environment for beneficial insects.
5. Use the most environmentally sound solution to solve problems.
• Use biological controls for insects.
• Use insect traps.
• Live with a low level of plant damage.
• Use nontoxic solutions to pests.
6. Use pesticides correctly.
• Follow pesticide label directions for rate, application, and safety.
• Match pesticide with pest.
• Use correct application rate.
• Buy only what you need.
7. Store and dispose of pesticides properly.
• Buy in small quantities.
• Store in secured area.
• Dispose of in accordance with federal, state, and local regulations.

Nutrient management BMPs you should implement in your garden include:

1. Compost garden organic materials.
• Retain dead plant materials such as leaves and seed free weeds in the garden ecosystem.
• Create nutrient rich organic material.
• Reduce materials sent to landfills.
2. Build a healthy soil.
• Add organic matter such as compost to enhance structure, aeration, water, and nutrient holding capacity of the soil.
• Prepare soil correctly.
• Maintain a slightly acid soil (pH 6.0 to 6.5).
• Build a biologically active, healthy soil through regular additions of organic matter.
• Grow annual cover crops to provide additional organic matter.
3. Test soil before applying fertilizers.
• Soil tests will measure the amounts of plant nutrients already available in the soil.
• Nitrogen (N), phosphorus (P), potassium (K), and sulfur (S).
• Soil tests also measure pH and percent of organic matter.
• Soil samples should be taken to a depth of 12 inches.
4. Apply correct type and rate of fertilizers based on soil test.
• Types of fertilizers.
• Organic fertilizer
• Manure, compost, cottonseed meal, blood meal, and bone meal.
• Organic fertilizers supply necessary plant nutrients while improving the soil structure, aeration, and water-holding capacity.
• Materials vary widely in their nutrient contents.
• Inorganic fertilizer.
• Chemically manufactured with exact nutrient content.
• Easy to apply, need relatively small amounts.
• Reduces loss of nutrients into the environment by applying at exact rates.
• Rates of fertilizer should provide nutrients only up to the level needed by the plants being grown.
5. Time fertilizer applications correctly.
• Supply fertilizer only as needed by plants.
• Apply at correct growth stage or time of year.

Erosion control BMPs you should consider in your garden include:

1. Protect your soil surfaces vulnerable to erosion.
• Bare soil surfaces are vulnerable to erosion.
• Mulches reduce erosion.
• Organic mulches include bark, sawdust, straw, and/or grass clippings.
• Inorganic mulches include permeable or impermeable plastic sheeting and/or rock.
• Cover crops such as oat and clover reduce erosion.
• Reduce intensity of water droplets on soil surfaces through protection by mulch and sprinkler management.
2. Improve your soil structure.
• Helps soils resist erosion processes.
• Addition of organic matter increases soil water-holding capacity and improves soil structure.
• Compost.
• Dead plant materials--leaves, grass clippings.
• Waste products--sawdust.
• Tilled in cover crops.
3. Perform tillage operations when appropriate.
• Tilling wet soil damages soil structure.

Water management BMPs you should implement in your garden include:

1. Use only as much water as necessary.
• Repair all leaks in hoses and faucets.
• Apply water only when plants require irrigation; don't water too often.
• Apply only as much water as needed; never over-water.
• Water enough to saturate soil only through the plant root zone.
• Reduces leaching of nutrients and pesticides.
2. Design your garden irrigation system for maximum efficiency.
• Apply water at a rate that can be absorbed by soil--avoid runoff.
• Drip lines and directed pop-up sprinklers apply water exactly and efficiently.
• Strive for uniform water application.
• Water only areas containing plants, not sidewalks, decks, parking lots, or streets.

This brochure, WQ-29, was prepared by R. L. Mahler, J. Robbins, and K. A. Loeffelman, Soil Science Division, University of Idaho, Moscow, Idaho 83844. Robbins is the Extension Agricultural Agent, Blaine County, Hailey, ID.

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Revised: January 3, 2003

URL: http://www.uidaho.edu/wq/wqbr/wqbr29.html