Last night, Wayne Porter, the Area Horticulture Agent from Mississippi State University Extension Service, presented a workshop on organic gardening. The information was for home gardeners, not for those wanting to sell their produce. If you're local, you might want to attend some of his workshops at the MS State Extension office in Lamar County.
He discussed the three primary concepts in organic gardening. First, he said that the building and maintaining the soil's organic content is important especially in the south. Rainfall and high temperatures break down organic matter much faster than in a cooler climates. Before planting it would be beneficial to have your soil tested so that you know what nutrients your soil needs. The testing should also give you the pH (or alkaline) of the soil. Ideally, the pH should be between 4.7 and 6.5 for vegetables. Here in Mississippi soils are acidic and need something like sulfur to lower the levels. Other adjusters include wood ash, organic matter, crushed shells and limestone. Organic matter is material that was once living.
Secondly, natural materials should be the source of your soil's mineral nutrients. Sources of organic matter include cover crops (like rye or wheat), compost, manure, crop residue and dead organisms. Cover crops are grown to control erosion and can be incorporated into the soil as green manure. Composting is a great way to deal with plant residue and is an essential component of organic gardening.
Using cultural and biologival pest control is the third concept in organic gardening. If necessary, you can purchase organic fertilizer, like blood meal, green sand, fish fertilizer, cottonseed meal, or manure. The advantage of purchasing organic fertilizer is that these fertilizers gradually release nitrogen through out the growing season. Depending on the size of your garden, the cost may make it make it difficult to get the required amount of material. For example, you would need 1,000 lbs of chicken maunre per acre to get the necessary nutrients for your plants. Also know that fresh chicken manure contains large amounts of ammonia and can damage plants. There is no guarantee that the product is organic if it's not labeled certified organic.
The healthier the plants, the less susceptible they will be to disease. Some of the strategies for disease management include crop rotation, proper plant placement, purchasing plants that are disease resistant, proper watering, and weed control. Also, if the seeds are planted at the correct time and in the ideal temperature they will have a better chance of survival. There are products like Neem Oil, Spinosad, sodium bicarbonate, Diatimaceous Earth, lime-sulfur, Rotenone Insecticide, or Bordeaux mix that can protect against predators and disease, but there are other options if you don't feel comfortable using these products. There are beneficial insects like ladybugs and praying mantis that can keep harmful insects in check or you can practice bagging of fruit, shaking, and hand picking. Ideally, planting varieties that are resistant to disease, are rapidly growing, and have a shorter growing season will decrease the chance of insect and disease. An additional problem is weed management. Tilling, flame cultivation, hand pulling, hoeing and mulch are all traditional methods of reducing weeds.
If you are interested in gardening organically, start by identifying your problem areas, gather information on management strategies, develop a list of resources, practice daily scouting, take immediate action, and practice Integrated Pest Management.
Additional resources: Sustainable Agriculture and Research and National Substaniable Agriculture Information Service