Last years carrots were rubbish. They didn't germinate, the weeds got on top of the second sowing which was too late. I thought of giving up on growing carrots. Instead this year I grew 4 times as many using fresh seed, fed the soil in advance, staggering the sowing, and lifting the protective net to weed and thin. Add to these factors the early dry spell and subsequent rainfall in June, July and August. Result: a bumper crop of cylindrical roots coming up clean without root fly tunnelling or forking. I think I've cracked it. For the first time after harvesting today I am having doubts that I may have overdone things. But then you can't have too much of a good thing!