What is organic gardening?
Gardening without the use of synthetic fertilizers, herbicides or pesticides

Organic matter is maintained in the soil through the use of compost, animal manure, and green manures.

For more information about the process of organic certification, the web sites of two agencies certifying organic growers in Michigan can be visited.

Most of the N used in modern industrial agriculture is taken from the atmosphere. Under high temperatures and pressures, obtained using fossil fuels such as natural gas, the nitrogen molecule (N₂) can be combined with hydrogen (H₂) to form an ammonium molecule NH₄, which is useful to plants. It can also be mixed with oxygen and chemically converted to nitrate (NO₃), which can be used by plants.

The history of protected plant cultivation or agriculture is very interesting but beyond this discussion. The key point is that there is evidence of the Chinese using manure as early as 4000 BC and it is likely many other cultures did also. The Romans used animal manure and crop residues to increase the fertility of the soil. By growing certain plants that are good nutrient scavengers with deep root systems and then plowing these plants into the soil, nutrients can be made available for the next crop. Animal waste products such as blood meal, bone meal, and hoof and horn meal were used starting in the 1800's .

Where does nitrogen in biological systems come from? The air is 80% nitrogen as nitrogen gas. Can plants use this? Not directly, but some bacteria - Rhizobium - can fiz nitrogen with the help of plants. Infect the roots of these plants - the plants provide food (sugars) and the bactierium fix nitrogen and provide some back to the pant - an ultimate symbiotic relationship! Many of the nitrogen fixing plants are called legumes. The plants can grow larger with the nitrogen and provide more carbon. This nitrogen can be used by other plants as the original nitrogen fixing plant decays. We can grow nitrogen fertilizer using crops like alfalfa and soybeans and other legumes. We can then use the fresh, dried, or decomposed plant as a fertilizer.

The traditional source of soil organic matter has been animal manures. Dairy and beef cow, horse, sheep, swine, and poultry manure can be spread on organic land and incorporated. Animal manure has been the primary source of nutrients for hundreds if not thousands of years, up until the last century. There are recent concerns about the presence of certain bacteria in the manure that if allowed to contaminate crops may effect the food safety of fresh fruits and vegetables. Part of the more recent concern has to do with how animals are fed, housed and treated with antibiotics.

Another very old, traditional source of organic matter and nutrients is growing plants on the land and then plowing them into the soil to decay and release nutrients. Crops grown to add nutrients to the soil are called green manures. Some plant species are selected as cover crops or green manures, because of efficient, deep root systems that bring nutrients up to the soil surface, others because they are hardy or more tolerant of nutrient, moisture or environmental stresses. The most important green manures are plants that together with bacteria are able to capture nitrogen from the atmosphere and make it available to plants. These plants are referred to as nitrogen fixers or legumes and include plants like alfalfa, clover, and soybeans. To use green manures will require rotations so that not all of the garden is constantly producing crops.

A third primary source of organic matter and nutrients, particularly for smaller plots of land or gardens is compost. Compost is the end product of biological breakdown of organic matter. Composting or breakdown can result from fungal activity at lower temperatures (<90 F) and bacterial activity at higher temperatures (from 120 to 160F). During composting, carbon from the organic matter is lost as carbon dioxide and heat and water are generated. The resulting material has more concentrated nutrients and can be used as a fertilizer as well as a source of organic matter for soil microorganisms.

We could easily spend hours discussing compost and how to make it efficiently. Compost should be an integral part of small scale or home organic gardening. Materials like yard waste - leaves, grass clippings, undesirables from the garden (weeds), and garden waste can be combined with animal manure or

hay or straw, kitchen or food processing waste to provide a biological digestor. Provided there is adequate carbon (brown materials like leaves and straw), nitrogen (green materials like grass clippings or manure or nitrogen fertilizers), moisture (water), air flow (oxygen) and enough critical mass (approximately 3'x3'x3'), bacterial activity with bring the temperature of the pile up to between 140 and `60F. Compost does not have to be fast, but finished compost should be weed free, nutrient rich, and relatively stable. It is not very difficult, but it does take some time and effort to get the techniques down. Before compost is used in the garden, it should be aged for some time after it is done heating. Compost can be spread as a layer on the soil surface but would be more available and useful if it is concentrated in the planting hole prior to setting transplants or under/in seed rows prior to sowing.

There are naturally occurring fertilizers or amendments that are acceptable for certified organic production. They can be categorized as either mineral derived, animal derived, or plant derived. Following is a table of several organic fertilizers and a range of rates they can be applied to the garden (in pounds (lbs) per 100 square feet of garden area). Examples of mineral derived organic fertilizers are mined phosphates either in the form of raw rock phosphate, colloidal rock phosphate, or black rock phosphate; a mined potassium silicate based mineral from New Jersey called greensand; lime, which is mined calcium and magnesium carbonate; gypsum, which is calcium sulfate; either potassium sulfate or potassium magnesium sulfate (sol-po-mag) that are also mined, and elemental sulfur. There is a large, naturally occurring deposit of nitrate of soda, or sodium nitrate in Chile, South America. Sodium nitrate is a very water soluble salt that is usually not considered acceptable.

Examples of animal derived organic fertilizers are blood meal (dried blood), bone meal, feather meal, fish meal or fish emulsion, and oyster shell lime. There are some concerns about the safety of these fertilizers when they are derived from poorly managed animals or animals that were not produced organically.

Examples of plant derived fertilizers include alfalfa meal, soybean meal, cotton seed meal, sea weed or kelp based materials, and wood ash. As with some animal derived nutrient sources, there is reservation about using cotton seed meal derived from cotton that is often heavily sprayed with insecticides. Since genetic modified organisms are not allowed, and more than half of the soybeans in the United States were GMO’s, soybean meal may also become unacceptable. Alfalfa is an excellent source of nitrogen and nutrients, but the price is not supportive of large scale use as a fertilizer.

As you get deeper and deeper into the philosophy of organic agriculture, you become less likely to look at plants as weeds. However, uninvited volunteers will compete for nutrients, water and light. Chemical agriculture makes use of herbicides (chemicals that kill plants) to prevent the growth of broad leaf weeds and grasses. Chemical herbicides are not allowed with organic certification. There currently is research into using naturally occurring compounds for weed control. Corn gluten is being tested as a pre-emergent (stops new weeds from growing) broad leaf weed control.

Weed control is based on routine physical cultivation, crop rotations, mulches, and planting cover crops in combination with cultivation. Non chemical weed control is more than hand hoeing. Soil preparation, developing balanced nutrient levels, and incorporating green manures can help reduce seed populations. Increased populations of soil macroorganisms that eat seeds can also reduce the number of weed seeds. One organic farm consultant reported that the presence of certain weeds could indicate a certain type of nutrient deficiency, pH problem or a nutrient imbalance. It is also important to try to exclude weed seeds by mowing or removing overgrown areas around the gardens.

Even with these options there will still be some mechanical hand weeding. As I learned this past year, weeding goes a lot faster if you have the right equipment and you use it at the correct time. This year I used a stir-up hoe for the first time. Using it early when the weeds were very little made the job very easy. While weeds may get started, the important thing is to not let them colonize or go to seed. A non chemical form of weeding that is acceptable for organic certification is called flaming. The very young seedlings are torched with a flame thrower type propane fired burner.

Covering the soil surface to prevent seed germination or mulching is a very effective means of weed control. There are many different types of mulches. Plastic or fabric matting are available in a variety of sizes and shapes. Some high carbon low nitrogen materials like bark, wood chips, or sawdust that would not be acceptable for soil incorporation can be used on the soil surface as long as they are not deeply incorporated into the soil. Straw and hay can be used as mulch and will break down and increase organic matter. Leaves and grass clippings can also be used as mulch as long as weed seed is not an issue. The virtues of heavy mulching year round once the ground has been prepare are outlined in a book titled "The Ruth Stout No-Work Garden Book" (Rodale Press, Emmaus, Penna, 1971).

When weeds do occur, consider them a resource. Most "weed" species are effect accumulators of nutrients. Nettles, yarrow, dandelion and others can grow where nutrient levels are low. If collected before seeds form, they make an excellent addition to the compost pile. Of course, a prime rule of any type of gardening is don’t let uninvited volunteers go to seed.

Organic options for control of pests and diseases

The widespread use of chemical pest and disease controls allows large mono-culture plots of varieties that are susceptible to insects and diseases. It also makes non chemical insect and disease control more difficult since many naturally occurring controls have been eliminated due to the use of chemicals. Many of the more pest and disease resistant cultivars are also no longer available. Commercial agriculture is move towards reduced chemical use and systems based on integrated crop management

There are many non chemical options that can be used to prevent serious crop damage from insects or diseases. If you are already used to a silver bullet, use a chemical to kill anything that looks suspicions approach, one of the first steps is to get used to paying more attention and depending on many different strategies as opposed to just one. It takes time to unlearn some methods.

One of the first steps is to develop a garden plan that uses crop rotations. Plants like tomatoes or potatoes and many others should not be planted in the same location each year. Part of the organic certification process is showing records and plans to routinely change the production location of crops. Part of the planning process can also include grouping certain plants that do well together, companion planting, and not grouping plants that have similar insect or disease problems. Mixed plantings, perhaps even several small plantings of a crop rather than one large mass planting can help reduce both insects and diseases. Also plan to give plants adequate space so there will be enough light and no excessive crowding which can weaken plants resulting in a greater susceptibility to insects and diseases. If you expect insect damage, increase the amount planted to allow for adequate harvests.

Another part of the planning process is selecting varieties resistant to insects and diseases. You can also buy or grow transplants carefully so they are insect and disease free at planting. Once crops are planted, inspect crops frequently so pest populations can be identified early. Provide adequate water and fertilizer to provide healthy growth, but don’t over fertilize which may lead to soft, succulent growth possibly more susceptible to insect infestation or disease infection.

Cultural techniques will also help. Clean up garden waste when fruiting or harvest is complete. This may remove breeding or overwintering places. In some cases mulches may help (they will definitely help keep moisture and nutrients in and weeds out). Eliminate or exclude volunteers (weeds). Mechanical control such as hand picking larger insects or pruning out infested plant parts. A strong spray of water can be used to remove pests.

Biological pest control involves systems that favor or invite predatory or parasitic beneficial insects. In some cases predators or parasites are bought and released, for example ladybugs or lacewings and certain parasitic wasps. Biological control may include trap or sacrifice crops that will attract pests away from more desired plants.

There are some sprays that are considered acceptable for organic certification. Some examples are Bt formulations for worm control, insecticidal soap, and a living fungus that attacks insects (Botanigard). Some sprays may be allowed on an emergency basis when severe crop failure is imminent. Compost teas, or water extracts of compost have also been used to help prevent insect attack and disease infection. Other preventative sprays include garlic barrier and hot pepper wax.