Help Please. I need an organic control for Damping Off of my carrots in the garden bed.

History: Have been having trouble germinating carrots for several years, at least I thought that was the issue. I've tried many methods to improve the germination rate, but nothing seemed to work. Last attempt at seeding, I covered the seed bed with a very thin layer of old straw, and lo and behold, after only 7 or 8 days, I had amazing germination. The cotyledons were pushing right through the very light straw layer. I was so pleased. At day 12 there was scarcely a carrot to be seen. That's when I realized that Damping must be my problem. Internet research also showed images of what Damp looks like in beans too... and I have that this year for the first time. Beets have also had lousy "germination". I have been faithful in keeping the seed bed moist. Garden is in full sun. Soil is well drained, compost -rich, sandy loam.

Controls: I read that compost tea will help control the fungus, but after forty years of composting my garden is so rich in compost it is the envy of all my gardening friends. Will tea be much of an improvement over pure compost. I have even used pure screened compost to cover the seeds.

So what are your experiences and advice please?