What causes blossom end rot in tomatoes?

Answer 1

It can be many issues including a blight. Usually the seeds are treated for this before planting and some varieties are bred to be resistant to blight. If the tomatoes are touching the ground, try supporting them with some newspaper mulch or a small pile of netting, if the ground is constantly wet.
It can also (rarely) be a sign of insect damage that occurred during blossoming or pollination. When I lived on the farm, we added 1 Tablespoon of Epsom salts to the soil before setting out the tomato plant and this seemed to prevent some of the blossom rot, so lack of calcium (or other nutrient) could be an issue as well. You should have you soil tested every year before planting to see if you need to add amendments.

Answer 2

Inconsistent watering and lack of calcium. Water your plants regularly and thoroughly. I "plant" gallon milk jugs with holes poked in them in between my tomatoes and put the water in the jugs. This way the water is distributed to the roots instead of landing on the leaves and possibly causing fungus. For the calcium, try crushing some egg shells and either mixing them into the soil or soaking them in the water you plan to water with. I throw shells into my milk jugs.

Answer 3

your plants need calcuim sprinkle 1/4 c powdered milk around each plant and water

Answer 4

Calcium deficiency.

Answer 5

http://pubs.caes.uga.edu/caespubs/horticulture/blossom-rot.html

Answer 6

irregular watering schedule