A few weekends ago I mentioned that I had built an enclosed greenhouse on my unheated sunporch. The new growing space is in front of windows but it also contains two shelving units with fluorescent lights plus a small space heater connected to a thermostat.
It’s small enough to put anywhere and it can be disassembled when warm weather returns.
I got the PVC corner fixtures from U.S. Plastic. I bought pieces that fit over 1/2″ PVC pipe but noted that their corner pieces are slightly larger than standard hardware PVC pipe. I simple wrapped the ends of each pipe piece with masking tape to make it fit tightly. I used #8 3/4″ screws to hold the pipe in the sockets, after drilling a 1/8″ pilot hole for each.
I covered the greenhouse with the thin clear plastic used to seal windows from winter drafts. I used the double-sided tape in the package to attach the plastic to the pipe frame. I simply overlapped the plastic sheet by 3′ at the front of the unit so I can slide in and out without losing heat.
It works great – much cheaper than an outdoor greenhouse!