Simple, Low-Tech Trick That Keeps Your Greenhouse Warm (and Cool)

| 1/15/2014 9:08:00 AM

Tags: greenhouses, passive solar, home heating, Florida, David Goodman,

Greenhouse/GreenhouseWhen I first moved to North Florida and hit winter for the first time, I realized I was no longer in the land of balmy beaches and 60-degree overnight lows in December. The first frosts hit us in November, then we had a couple of freezes (including one that dropped into the teens overnight) which made short work of the papaya, mangoes and other tropical plants I had lovingly planted in the yard the previous summer.

I know, "cry me a river," you Northerners are thinking. "It's 30 below here!" Sorry about that. No really. I feel terrible. In fact, there's a tiny violin playing behind me.

This post may not help you all that much if you're dealing with those kind of extremes, but the concept may still prove valuable with some tweaking.

If you live in about USDA zone 8 south, having a simple single-layer greenhouse can get you through the winter easily. Here's the one I bought a couple of years ago. Simple and it works. I suppose I could have built one - but I'm pretty sure I couldn't have done it for the price I paid for that model. Anyhow - back to my story.

When I set up the greenhouse for the first time, I was excited to feel how hot it got inside as soon as I zipped the doors and windows shut. I loaded it up with all my cold-sensitve plants, then put a thermometer inside so I could keep an eye on the temperature.

Within the next few days, there was a frost predicted. The night of the frost, I shut up the greenhouse and went inside. Late at night I went out to check the thermometer. It was almost as cold inside the greenhouse as it was outside! That wasn't good. I quickly strung up a bunch of Christmas lights, plus a few flood lamps, then plugged it all in via an extension cord.

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