Planters Pride DOM10200 Greenhouse Humidity Dome, 10 by 20-Inch

Flimsy piece of over priced junk!

2.5 rating from me. I don't care for these, I'll be honest. They make better supports under the trays than they do for their intended purpose. (w/o one of these underneath, the trays are prone to cracking in the middle when moved.)That said, they are good for temporary use. (The time after seeding until the seeds sprout.) If you can find it locally all the better, because I'll be honest I don't find this product worth the added shipping/ additional mark-ups. If you absolutely have to look online for this, really you're better off starting with the taller domes the same company offers.Seriously. Get the taller dome. The taller domes have the same problems with flimsiness and cracked corners, but they will help your success rate tremendously. That is unless you have access to a greenhouse and that type of humidity. But I don't. My arid apartment offers no help to beginning seedlings. Left open, without a dome, the seed trays dry out in the matter of days and the leaves wilt in the dry air. The clear domes prevent this, unless you overwatered, then they are a death trap. That brings another reason I don't care for these. No vents. The taller domes have vents. Vents are helpful reducing excess humidity and keeping the trays from overheating.Usually these shorter domes come included in the planting sets. If you don't have the taller dome, use these as a stop gap. The dome will also serve to keep the trays warm (if you have the tray close enough to a light source.) In my growing set up the domes eliminate the need for heating mats.