Imho, BER is mainly caused by extreme temperatures of the soil that prevent the roots from absorbing calcium to nourish the fruits. Insufficient watering then "helps" in two ways: doesn't cool the soil and makes transportation of nutrients including calcium within the plant difficult.
The usual advise I get is to use either calcium nitrate (max. 0.5% solution in water) or Wuxal Calcium and spray the leaves. It makes good sense to me: if the roots are "out of order", the leaves can still absorb nutrients as well. Even though just to a certain extent.
The trouble is that this should be applied before the first heat wave so that calcium deficiency is prevented. And repeated if need be. If we apply this procedure only after we detect BER in tomato fruit, it affects just newly developing tomatoes. It doesn't help those that were formed during the time the plant didn't have enough Ca. It's obviously no "miracle cure".
And one more thing: as BER is physiological and not caused by a pathogen, I normally eat the fruit. Just cut off the bad part and enjoy the rest. Actually, it's only an impression of mine, but I often think the BER fruit are sweeter than the rest.
Milan HP
|