Posted: 14/07/2014 at 09:09
KEF, it's not so much letting the soil or compost dry out but erratic watering patterns. Plant stress is thought to be the underlying cause of BER, with erratic watering patterns topping the list of contributing factors.
But I've had BER on plants that have enjoyed utterly regular, consistent watering patterns. There are obviously other factors that can stress a plant - sudden, rapid temperature changes; possibly even strong winds, whatever. Still, we've come a long way with BER from the days when the answer was said to be insufficient calcium in the soil. Roll on science.
It still remains a mystery why some varieties - mainly the plums, San Marzano, etc - can be more prone to BER than other varieties. I've often had plums in the same bed alongside other varieties - identical soil, identical watering and climatic conditions - with the plums suffering BER while the other varieties remain clean. You'd have to assume there's some genetic factor at work. Roll on science again.