So at the end of the summer, Chris got this brilliant idea. Why not build frames over the vegetable beds and arbours, cover them with sheet plastic, and see what happens!
At best we thought it would keep frost and snow from accumulating on the beds, allowing us to plant even earlier in the spring. We had a thought that we'd be able to leave some veggies in the "green houses" for a few weeks or so, and it would just be like they were in a refridgerator. But so far, the experiment has exceeded all expectations.
Not only has the covers protected the vegetables from frost, but the air inside is at least 2-4 degrees warmer than the outside! The soil is also retaining moisture; we can see that each afternoon when the inside walls are covered with condensation and dew.
As for the vegetables, they are flourishing! Not only has the covers protected them from frost, but instead of just keeping the plants dormant as they would in a refrisgerator, they are actually still growing! Three weeks ago I harvested the last of the carrots, but we still have beets, scallions, romaine lettuce, and our swiss chard in the first two beds.
As this is an experiment, the last bed we decided to leave uncovered (as there were no vegetables left in that bed) to act as our control bed. That way in the spring, we can see if covering the beds really makes a difference in how early we can plant next year's crop.
That being said, even if there is no difference in how early we can plant next year, I am sure we'll still use the covers again next fall. The fact alone that it is the 18th of November, and we have vegetables still growing is enough of a reason to do it again. In fact, we plan to plant specific "Winter" crops late Summer/early Autumn, such as kale, beets, lettuce, and scallions to see how long we can keep them in the beds. I am thinking we could even plant some cooking onions in the fall, and have them ready even earlier in the summer, perhaps getting two crops next season instead of one!
We had to change the design of the covers slightly once they were up for a couple weeks. The first design consisted of wooden 1 inch strapping forming a triangular prism over the beds and arbours, over which we stapled the sheeting, and reinforced with duct tape. But after a couple rain and a good wind storm, the pieces of sheeting began to seperate and pull away from the frames. So Chris purchased more strapping, and sandwiched the plastic between two lengths of lumber. So far that seems to be holding quite well (we also switch to contractor-grade outdoor duct tape!), and we'll just have to see what shape they're in in the Spring.
The frames may not be the prettiest, but if they mean our growing season is extended, and the amount of food produced increases, than it's worth it!