If you wanted to Seedling Carrots Id get these XL 72 Cell Trays. Its rather hard to seedling carrots as they need some room to root. but to just germinate. Think these do better than other ways trying to seedling carrots. Theres a whole at the bottom if root wanted to grow outside the cell. The tray looks like its made out of hard plastic but they are surpisingly just made out of flimsy plastic that can bend and brake in time over extended use or mal care. I hope these have long lasting durablity but getting them after seeing them in the mail I question. May have to see for yourselves. I cant find any other xL trays like this so I suppose its worth a try.