I‘ve always had great luck with tomatoes in my garden. This year, however, all of the tomatoes look beautiful on top, but are black and decayed on the bottom. Morover, the plants themselves seem more brittle and prone to wilt. . . what‘s going on?
Probably blossom end rot, which is mostly a calcium deficiency, also related to water stress (It has been hot this year). Apply some dolomite (finely ground, white). You can use other types of lime if dolomite is not available. Lime raises the ph of the soil (makes it less acid), and adds calcium to the soil. Dolomitic limestone also gives you a little magnesium for the same money. Organic amendments to the soil, some fertilizers, and just plant growth over time tend to acidify the soil. Plan to till some lime into the garden every 2 or 3 years.
wilt could very well be your problem.verticillium wilt. this is a soil borne fungus that infects through the roots. usually it causes leaves to drop just above about 12 inches above the soil line which aids in sunburned fruit. usually the tops of the plants stay green, but the lower stem can have browning veins and spots. to diagnose, make a vertical slice in the main stem just above the soil into the vascular tissue and look for browning. to help, moving to another location for planting is a good idea since the fungus can lay dormant in the soil for several years. a cereal grain crop rotation and weed free garden are also helpful
If you are in an area that has had a lot of rain, it's probably potato blight, which affects all members of the Solanaceae family, not just potatoes. If it is blight, the leaves will have also been affected with brown patches starting at the edges and eventually killing the whole leaf. You need to remove affected leaves and fruit and burn them or dispose of them in such a way that spores can't be transferred from them onto healthy plants/fruit. Though it may be too late. The other possibility is blossom end rot, which is caused by insufficient watering.
