The media beds under each stack is a 2'x3'x8" mixing tub bought at Home Depot for $12.50. They are filled with pea gravel. This one is growing Pineapples and Aloe. The pineapples have been doing nicely but ripen in less than a year and are about 5-inches in size. I am hoping to get that size routinely since I could see a niche market for "Personal Size Pineapples." If I had known about TCLynx's new media beds before committing to this, I would have gone that route.