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Low-tech greenhouses extend the growing season

Our growing season for tender plants usually ends in mid to late November with a killing frost. But we can move fall tomato and pepper plants into a cheap homemade greenhouse to add extra heat for ripening and postpone the frost date. It would be nice if we could extend our season to Christmas, but we haven’t gotten quite that far yet.

Of course more cold-hardy plants can handle frost or even freeze, but when it gets really cold, they stop growing. This year I am also moving potted broccoli and cauliflower into the greenhouse, in hopes that the extra heat will serve to keep them growing and harestable through the winter. Otherwise we’d have to wait for warmer spring weather to continue their growth – and that sometimes ends with them bolting (flowering and going to seed), instead of heading.

In the spring the greenhouse is perfect for starting plants early. Actually the germination is done in trays at a southeast-facing window inside. But as the seedlings reach transplantable age, they go into separate containers and out into the greenhouse. We’ll tell more about this in a separate post.

We have two low-tech greenhouses to help extend our seasons. The smaller is on our deck on the southeast side, and the larger is attached to the southwest side of our house. Both are made of pvc pipe with some 1×2 bracing and covered with six-mil polyethylene plastic sheeting. The sheeting is attached at the top by being clamped between two 1x2s, but the rest is held in place with cheap spring clamps.

The sheeting is replaced seasonally, and is the only ongoing cost. I found that four-mil sheeting will not last long enough, but six-mil does okay.

We do not try to heat the greenhouses, but I do have water containers to help them hold the day’s heat and prevent night freezes as long as possible in the fall.

The larger one has served now for two years, and the smaller for a year.

Both will ultimately be replaced (we hope) by more permanent greenhouses, but for now, on a limited budget, they serve quite well. Neither cost more than a hundred dollars, though the larger one might go a bit over that now, with the recent rise in prices.

Here are some photos of our construction of the larger, so you can get a better mental picture:

Rebar anchors the pipes to the ground.

Rebar was driven to anchor one end of the hoops. Then the plastic pipe hoops were slid over the rebar.

Get's a little heady sniffing the glue on the other end.

Get's a little heady sniffing the glue on the other end.

PVC tee is cut in half for end anchor

Plastic tees were cut in half and screwed to a 2x2 which was attached to the wall with masonry anchors.

Mama is happy with the results so far.

Mama is happy with the results so far.

Spring clamps from Harbor Freight

The plastic sheeting was held by cheap spring clamps from Harbor Freight

Nearly finished - now to make up tables from recycled pallets.

Nearly finished - now to make up tables from recycled pallets.

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