So I like watching Charles Dowding on YouTube. I've watched a lot of his videos, many numerous times as I let them play in the background. Just watched his very latest video about a hot bed for carrots. LOL, in a good way. He has said previously that the people who say not to plant carrots in a bed with compost were digging the compost in to the soil and the taproots were hitting bits of compost and forking. So he tries an experiment of growing carrots in the winter on top of a hot manure pile with the very top being unsifted homemade compost. The carrots sprouted and grew but only to about the depth of the homemade compost. It was a totally cool experiment. I was wondering what would happen with a root crop that was planted on top of a medium that would be constantly shrinking in volume, but the manure pile didn't shrink as much as I expected it would. So basically the thought is that he needed to add more growing medium. I think I would have also covered it in plastic to maintain the heat from the pile.