I love growing from seed, but the typical cell trays available from local sources are pretty flimsy and hold up for only 1-2 growing seasons before the bottoms are broken or the tray is sagging. I'd like something sturdy and reusable where the seedlings can be easily popped out without wrecking the tray. I can't tell from the online adverts whether a tray fits my criteria or is more of the same throwaway quality. I want to try the varying size plug trays to experiment with growing perennials for my own use (mass plantings) and would appreciate a recommendation available for retail purchase.