Question: What is the best recovery plan for my soil if I had early blight last year? How many years do I have to wait until I can plant nightshade crops in that garden bed again?
Answer: Early blight is common in the gardening world and especially picks on tomatoes; however, it’s controllable. First, let me tell you the common advice and why I don’t agree. Then, I’ll tell you the solution that actually works for me.
Common advice: Prune or stake plants to improve air circulation. Disinfect pruning shears with 1 part bleach to 4 parts water after each cut.
Dirt Doctor response: Careful pruning is OK; bleach isn’t. Hydrogen peroxide is a better choice.
Common advice: Drip irrigation and soaker hoses help keep foliage dry. Only water during the day.
Dirt Doctor response: I don’t object to watering the foliage under a proper organic program. It naturally rains at night anyway.
Common advice: Apply copper-based fungicides early.
Dirt Doctor response: Copper fungicides are toxic; I never use them.
Common advice: Maintain plant vigor. Stressed plants are more susceptible to early blight. Water plants regularly. Don’t fertilize until the plants are well established and in full blossom, and don’t mulch until the soil is warm.
Dirt Doctor response: I agree that stressed plants are more susceptible, but organic fertilizers can be used any time and mulch should cover the bare soil at all times.
Common advice: Rotate crops every two or three years. Avoid planting eggplant or potatoes where tomatoes were last planted.
Dirt Doctor response: I agree with Ruth Stout and Dr. William Albrecht that crop rotation is unnecessary and may actually lead to problems. Ms. Stout wondered why annuals needed to be rotated while perennials didn’t. Dr. Albrecht argued that rotation was the quickest way to “mine” and damage the soil.
The Dirt Doctor recommendation to avoid this common tomato disease is to choose well-adapted cultivars for your area; avoid all synthetic fertilizers (especially the high-nitrogen ones); and apply compost, lava sand, and whole ground cornmeal. Compost and lava sand can be used at 100 pounds each per 1,000 square feet or at a higher rate. Cornmeal should be applied at 20 pounds per 1,000 square feet. At the first sign of the disease, spray hydrogen peroxide (1 percent solution) or BioSafe, BioWash, or Serenade. -Howard Garrett, AKA “The Dirt Doctor”