Catalog descriptions of carrot varieties often refer to soil types.I have very little experience with clay soils but imagine that they are not the easiest for growing carrots.
I have multiple garden locations. I only try to grow carrots in well-cultivated soil but even so, it's gravelly
stuff! One problem is the rapid draining and the possibility of the roots splitting because of uneven moisture during their growth.
Shorter growth time, shorter carrots. It's best for me to grow short, quick-maturing varieties. Nelson Nantes is about as long as I'd care for them to grow. Really, I'd like even shorter and using pelleted seed and staggered sowings, can have a long carrot harvest, at least. But no ... DW likes looong
carrots! Of course, the longer that root, the more likely it will fork when it works its way around pebble. The more time it takes to grow, the more things that can go wrong
At one time, I had a garden in what must be described as sandy loam. Carrots grew well there