Carrots & Radish

Some people do sow radish with carrot, but I find the carrot seed so fine and fiddly that it's just easier to try to space it properly rather than blend with radish seed. As you'd pop out the radish, you'd expose some of the carrot root for enough time to attract the carrot fly. I think your best bet against carrot fly is to build a screened box cover over the carrot area. The little beggars can root through soil but not through screening. The other altnerative is to put the carrots high, as in an old bathtub. Carrot flies can't go above 2 ft in their flight.