|In our small garden, we plant only tomatoes. There is a disease that kills plants from bottom up, causing browning leaves and spots. Will solarization help or work, or do I need to not garden in that area for 2 to 3 years?
|The symptoms sound like either early or late blight, which are caused by different fungi. Early Blight overwinters on infected plant material, even seeds, so it's hard to completely remove the spore reservoir from the garden by cleaning up all the vines and fruit. Solarization may help, but it's temporary, and it can kill everything in the soil, not just the "baddies". It works slowly, whereas Late Blight may kill plants within a week. The fungus is always growing somewhere and releasingspores into the air, which moves on wind currents. It doesn't overwinter in your soil, so solarization won't help control it.
The soil could use a break from constant monocropping, but if you don't have room for a second plot, I suggest loading up the soil with good compost. Compost contains lots of helpful organisms which can work against disease organisms. Work a few inches into the existing soil, and then spread several inches on top of the soil as a barrier mulch. Once your tomatoes are planted, mulch with straw as well. Keep your plants healthy so they'll be in top condition to resist disease. Stake or cage them, and keep the lowest leaves from coming in direct contact with the ground. If you follow this practice every year, I'll bet the incidence of all disease will drop. Good Luck!