Many tomato plants have a common fungus on them and they are quickly overwhelmed by it. Their leaves turn yellow, they have spots on them and they have a kind of grey/brown on part of their leaves that end up looking like burnt paper, and they crumble when touched. The stems are also affected. If this sounds like your tomato plants, it is time to take some action!
Things You’ll Need:
Copper sprays, though they can be expensive, is the primary fungicide and is recommended as an organic alternative. Another option is liquid sulfur sprays. Once you have attracted the fungus, copper and/or sulfur sprays can prevent further development of the fungus on your plants.
One other more organic alternative that is highly effective is to spray the plants with a solution of 1 gallon of water mixed with 3 tablespoons of baking soda, 1 tablespoon of Epsom salts, and 2 tablespoons of non-concentrated lemon dishwashing soap. The baking soda will raise the ph level. It has been found that fungus, mold or mildew will not survive in a high ph “alkaline” environment. Spraying weekly with compost tea also seems to be effective at warding off fungus diseases. There has also been some evidence that extra calcium and the use of fertilizers containing ammonium offer some protection against certain types of fungus.
Other steps you can take to prevent the fungus from even starting on your plants are to: grow varieties that are more disease resistant, if you are planting in the ground, try crop rotation. Plant your tomatoes outside in the sunniest part of your vegetable plot. Never water the leaves, just the base of the plant. Some times a light layer of gravel on top of the soil will prevent soil borne funguses from reaching the plant itself. Gravel will also help the soil retain moisture during the hottest part of the day.
When you transplant tomato plants, bury the plants deeper than they were in the pot, all the way up to a few top leaves. Remove the leaves closest to the soil. Tomatoes are able to develop roots all along their stems so you can either dig a deeper hole or simply dig a shallow tunnel and lay the plant sideways. the plant will straighten up and grow toward the sun within a few days.
Pinch and remove any suckers or shoots that develop in the crotch joint of two branches. But go easy on pruning the rest of the plant. You can thin leaves to allow the sun to reach the ripening fruit, but it’s the leaves that are photosynthesizing and creating the sugars that give flavor to your tomatoes.
When the plant gets to a height of about 3 feet, it is a good idea to remove the lower 12″ of leaves, to avoid contact with the soil. These are usually the first leaves to develop fungus problems. They get the least amount of sun and soil born diseases can be splashed up onto them.