Something's Rotten...

See the sad, little tomato above?  This little guy has blossom-end rot (let's call it BER).  If you've had it (and you likely have) you know that this tomato will never properly ripen, nor will it be edible. Every year, I plant a blossom-end rot resistant variety (Parks Whopper Improved).  When I plant, I put the tomatoes deep into the soil or trench them, and place a calcium source (half a 1000 mg. calcium supplement, a calcium-based antacid, or finely-ground eggshells) in the hole with the plant. I thought that was it, that the plants were now protected from this problem, after all, BER is caused by a calcium deficiency.  That's true, but all the calcium in the world won't prevent BER if you have inadequate, irregular watering.  Too little water interferes with the plants ability to transport calcium into the tissues of the plant (and, as you may know, an over-abundance of water can cause fruit to split).  So this is a two-tiered problem, caused by calcium deficiency and inadequate watering.  (Having a resistant variety is good, too, as is a 4-year crop rotation).  By the way, peppers (especially bell) can also suffer from BER.
I will write more one day about the other reason I grow Whopper Improved...and other highly-disease resistant plants.