For the past two years, we have much damage from black spot. We used a copper soap spray this year but the damage is still pretty bad. Is there something we can till into the soil to stop this blight before planting?
Black Spot on Tomatoes
Certified GKH Gardening Expert
Typically, the best way to handle blight is to rotate the tomatoes to a new location for a year or two so that the blight dies out. If this is not an option for your garden, you can try treating the soil with fungicide at the end of this season and the beginning of the growing season next year. Also, plant your tomatoes further apart to encourage good airflow and water from below through drip irrigation to keep water off the leaves, which will help reduce the ability of the blight to take hold.