Hardening-off, a new techique
I recently learned that some horticulturalists advise, and ~ maybe ~ some commercial greenhouses practice, hardening-off of plant starts. How might that be done in a greenhouse? Well, it all seems to be a temperature thing.
You can imagine that a greenhouse with its furnace and air-conditioning, has pretty good control of the interior temperature. It may be run at a range of between 60o and 80o during a normal 24 hours. Turning things down to 45o and 65o may be easy enough during early spring. The plants are then off to the retailers where they will often be sold and kept outdoors.
I don't have "pretty good control" of much of anything. I do try to maintain my heated greenhouse at 60o to 80o but this year moved plants from the steadily filling greenhouse to the new shed-attached hoop house. The little 800w heater in there could keep things about 12o warmer than outdoors, overnight. If it was 27o outdoors, it was 39o in the hoop house . . !
That happened once. The little heater was capable to keeping the interior warm to above 40o other nights. I was happy enuf with that altho' I checked the remote thermometer every morning, well before sunrise. There is now a bigger heater here in the house that can sub for the 800w out there
Many of those plants went on to unheated protection under plastic in the yard. Some things are now out in the open during the days. Some of the cold hearty plants are already out in the garden. Hardening-off has been so much easier this year!
Shade is important, protecting the plants from the wind is important but pulling them out into the open anytime it is above 45o isn't worrisome. I should have set up some simple shelter with a dinky heater years ago!