Vegetable Gardening in Mississippi
Organic Gardening
Interest in organic gardening—using organic and natural materials for fertilization and disease and insect control—is increasing.
Much of the interest is on reducing or eliminating use of chemical pesticides for controlling insects and diseases. There is less interest in the use of natural and organic fertilizers.
Organic gardening in Mississippi faces some serious problems with the rapid loss of soil organic matter and severe insect and disease pressures on vegetable plants. Organic gardeners, to ensure the greatest chances for success, should have the garden soil tested for pH and nematodes.
Soils with a low pH (acid) can be corrected using limestone, ground oyster shells, wood ashes, or dolomitic limestone. Adding organic matter benefits soils with a high pH (alkaline).
Animal manures are the most widely used organic fertilizers. Unfortunately, their composition varies with the source, age, degree of rotting, water content, and amount and kind of litter used.
Most organic materials do not contain plant nutrients in balance with plant requirements and must be supplemented to correct these imbalances. A well-leached animal manure has an estimated fertilizer ratio of 1-1-1, or 20 pounds each of N, P2O5, and K2O per ton of manure. Besides being relatively low in nutrient content, the nutrients are available more slowly than nutrients from inorganic sources. This protects nutrients from leaching, but when a rapid change in nutrient level is needed, this can be a problem.
Controlling diseases and insects by natural means alone is difficult. Therefore, organic gardening is easier on a small scale than on a large scale.
To increase chances for success, organic gardeners should follow these practices:
- Plant disease- and nematode-resistant varieties.
- Use marigolds, solarization, and organic products like Clandosan 618 to control plant parasitic nematodes (see Extension Publication 483 Nematode Control in the Home Garden).
- Plant seeds from disease-free plants.
- Plant only healthy vegetable transplants.
- Place a cardboard collar around plant stems at ground level to prevent cutworm damage.
- Incorporate plant residues and animal manures early to allow sufficient time for them to decompose before planting.
- Use mulches to control weeds and keep soil from splashing onto the plants and fruit.
- Use aluminum foil or silver-painted plastic mulches to repel aphids and thrips that injure plants and also transmit plant viruses.
- Plant as early in the spring as possible to avoid some insect problems.
- Keep the garden free of weeds that may harbor diseases and insects.
- Hand-pick insects.
- Water during the day so plants are not wet at night. Remove diseased plants and plant parts from the garden.
- Control insects using biological controls and natural products.
- Rotate garden areas.
- Encourage natural insect predators. Trap slugs under boards and moist burlap laid on the ground, or use beer traps.
- Stay out of the garden when the plants are wet to prevent spreading diseases. Use fixed copper fungicides to control many fungus and bacterial leaf spots, anthracnose, and downy mildews. Do not use tobacco products while working in the garden. Mix different vegetables in a row to eliminate monocultures and the chance for a disease to spread rapidly.