I think people are referring to a solar swimming pool cover. They make clear ones that are like heavy duty bubble wrap. You can wrap your greenhouse in them like a little winter blanket.
Thanks! I looked at those the other day and wondered if they could be used. (swimming pool covers) The roof on my greehouse is sooo tall, it'd probably take a huge one.
Last year I put up heavy gauge plastic. I do have double walled polycarbonate but with the high cost of heating, I figure anything extra I can do would be worth it.
Bringing this back up - I'm investigating a clear 12 or 16mm pool cover for my 14x18 freestanding Turner, installed under the shade cloth I leave up year-round. I'm also investigating converting the fiberglass with bubblecap insulation to twin or triple-wall polycarbonate, but so far I'm not finding much information on whether the existing frame will support the added weight.
Has anyone tried this?
I just covererd my gh with a 14mil solar blanket. It gets pretty cold here in zone 6 so any additional warmth is appreciated. The vents are closed for the winter. My only problem now is that the blanket seems to keep it so air tight that the humidity is running up to 89% at night. Am concerned about detremental effects of too high humidity. Anybody else have this problem?
well, I fear that's asking for a botrytis outbreak. If you can keep the air moving rather briskly and keep up your early-morning spraying/treatment routine you might be fine. I find that keeping my growlights on at night also helps (have a comparable high-humidity problem at night even without installing the solar blanket yet). They're florescent daylight-spectrum tubes, not HID, so I don't think I'm really overdoing the light.
I seal not only my unpowered vents but the fan/exhausts as well once the night temps are regularly freezing or below. I do have a screen/storm door, so can at least open the house to fresh air whenever the temps are cooperative. But fungus is an ongoing problem that repeatedly taxes my procedures!
where did you get your 14mil blanket, and what size is it? I've seen smaller ones, but nothing of a size that will work on my Turner.