I tried to grow round carrots in a plastic container on the balcony, with the idea that round carrots wouldn't need as much soil depth as pointy ones. But one day the green parts above ground was completely covered in some white web, so I gave up on them.

I still like the idea of round carrots, so I may have to try again some day. I don't think I've seen them in the supermarket.

https://www.ufseeds.com/product/parisian-carrot-seeds/

What type of fertilizer do you use for carrots? The regular indoor flower variety or something special?