Posted: 10/06/2013 at 09:07
There's some good sensible advice in that link, Sue. I particularly like the caution against overwatering. I'd extend it to overfertilising, too. There's an old tomato saying: "More plants are killed by pampering than neglect".
The Blossom End Rot (BER) problem is an interesting one. It used to be tomato lore that it was caused simply by a lack of calcium and was remedied by digging the stuff into the soil.
Science now tells us that BER is certainly calcium-related but in terms of the plant being unable to distribute the calcium through its internal system to the fruit. You can have all the calcium in the world in the soil but the plant is unable to use it.
Unfortunately science can't tell us exactly why. The best guess is that it's stress-related, with the plant's physiology under duress and affected. There are potentially plenty of causes of plant stress - climate, culture, etc - so there's no simple answer.
The real mystery, though, is why some varieties are more prone to it than others. The link suggests larger-fruited varieties are more prone, but, in fact, it's the plum or egg shapes - San Marzano, etc - that are most vulnerable. I've had plum/egg varieties in the ground growing right beside beefsteaks and oblates. The plum or egg shapes have been riddled with BER, their immediate neighbours totally BER-free.
Who would be a tomato grower?