Agree with Tee Gee, having a flexible system is really useful, I use four of those 4 tier mini greenhouses....in spring they house all my seedlings (with the plastic covers on) before being hardened off, then they go outside as hardening off and direct sowing units, and I put growbags with pots on top for the tomatoes and have one three segment permanent staging with gravel for peppers and chillies. My greenhouse has a tiled floor though, presume you will have at least part as a bed?