Organic Methods to Rid Plants of Diseases

Cultural Controls

• Providing your plants with the care they need often prevents serious problems with diseases. It also helps plants recover from diseases so your other efforts aren't wasted. Choose varieties of plants that have resistance to common diseases, whenever possible. Avoid overhead or sprinkler irrigation, which can spread spores and keep foliage wet, encouraging fungal diseases. Don't crowd your plants, which can lead to poor air circulation and slow drying. To reduce humidity around plants, space them well, use drip irrigation or water your plants near the roots and make sure plants that need full sun aren't shaded. Don't work in the yard when it's wet because this can encourage disease spread. Limit your fertilizer use, especially high-nitrogen fertilizers, because these encourage tender new growth that's particularly susceptible to diseases.

Sanitation

• Keeping everything clean limits disease spread or the reintroduction of a diseases in subsequent years. Prune off and dispose of infected portions of plants before a fungal disease can produce spores. Remove plants that are affected by a viral or bacterial disease. At the end of the growing season, remove and dispose of plant debris and keep the area free of weeds, which can host diseases and harbor pests that spread pathogens. Unclean tools can spread fungi, bacteria and viruses to healthy plants, so soak their blades in a household disinfectant or a diluted bleach or rubbing alcohol mixture after each cut. Rinse or dry the tool before using it.

Crop Rotation and Other Considerations

• Proper crop rotation can prevent many disease problems. Do not plant crops or annual flowers from the same family in the same area of the garden two years in a row. A rotation pattern of three to five years is best. Where the soil contains pathogens, you can use chemical-free soil solarization. Soil solarization involves spreading a sheet of clear polyethylene over moist soil during the hottest part of the summer and leaving it in place for several weeks. The soil under the polyethylene will become hot enough to kill most pathogens and pests.

Organic Fungicides and Bactericides

• If other methods fail, you can use chemicals that are acceptable in organic gardening. You can buy organic products for many pests and diseases, including fungal and bacterial diseases.