I’ve used greenhouses for growing plumerias for a few years now. It’s a vital part of my growing program.
This is what I use the greenhouse for:
- Rooting: I want the cuttings I’m rooting in the hottest environment. I bag root, pot root, and gang root. They’re all in there.
- New rootings: Once rooted, and in a pot, I put it in the greenhouse for 4-8 weeks. The high heat accelerates root development and helps get the new plants well-established. Once I move it out, I put it in an area that only gets morning sun for a couple of weeks, then in full sun after that. This helps it get acclimated to direct sun.
- Grafts: Once I graft, the plant goes in the greenhouse
- Seedlings: All of my seedlings germinate in the greenhouse. Once they are a couple months old, I put them in a planter outside.
- Winter storage: I use the greenhouses to provide shelter from frost. Be careful: In my area I found that a greenhouse that is totally closed up actually acts like a refrigerator that can get up to 5 degrees colder than outside temps. So I leave all the windows and doors open through the winter.
I DON’T use it for heating over the winter. I refuse to pay outrageous rates to the electric company to accomplish this. We’re researching a solar panel kit, which would get us off the grid. We may consider it then.
Also we don’t use it for established plants. The problem is that the high heat encourages abnormal growth of the plant – elongated branches. Once low temperatures get above 55 in the spring, I bring the plants out until late fall.
I also like to put mid-cuts/stumps in the greenhouse. I believe the high heat encourages new branching.
Speaking of high heat, the experienced greenhouse growers I’ve talked to say it’s fine for the temp to get as high as 120. I’ve allowed that and have seen no negative consequences.
Also be aware that some greenhouse materials seem to amplify sun rays and can increase the chance of sunburn on your plants. I put a shade cloth (Home Depot – I think it’s a 75% shade) on the west wall of my western greenhouse and no problem with it since.
Make sure to use fans in your greenhouses, at least during the day. This keeps bugs from lighting on your plants and setting up residence.