Hashyanswered grow question 4 years ago I have just purchased a herbdryer rack its 60cm diameter and has 5 racks. It's sealed apart from a part at the bottom and one at the top. It's got a small carbon filter and fan at the top, like a pc fan. Next harvest I will hang this in a different room from my grow where the temps and humidity are better for a longer dry and hopefully it will take it longer to dry.