Oh no! A lot of our tomatoes have giant brown spots on the bottom. I did quite a bit of reading and searching the Internet, and it looks like we have Blossom End Rot, which is not a disease but a calcium deficiency. Because it’s been so hot, the tomatoes haven’t been able to take up enough calcium through their roots, and when it doesn’t reach the ends of the fruits, they simply stop developing and rot.
Fortunately, this isn’t a fungus or a disease – but having weak tomatoes like these on the plants can attract insects and fungus so we’ve been pulling them off. I quickly got some hydrated lime, diluted it in water, and added it to the tomatoes. Hopefully this will help prevent more blossom end rot from developing.
Tip for next year: Get the soil tested. BER can also be caused by too much nitrogen or too much of something else – if the tomato takes up too much nitrogen, it may not be able to get as much calcium it needs. Add hydrated lime if the pH is too acidic; an addition of rock phosphate may also help.