Better Living Through Permaculture: Crazy for Cold Frames

[IrateCitizen]

I’ve been crazy for cold frames for a couple of years now, and have begun to work them into my permaculture operation. Last winter, I built two out of plywood scavenged from the construction site I worked at, smacked them down in a part of the garden away from the house, filled them with leaf mulch and topsoil, and threw a couple of salvaged storm windows over the top. I planted them in late February with lettuce and spinach, and probably gained 2-3 weeks on the growing season. Here’s a picture of one of them in June:

(PICTURE IN ORIGINAL ARTICLE)

I learned two valuable lessons through this first project. First, it’s not difficult to build an effective cold frame for little to no money. Second, building a cold frame away from the house and exposed to the cold northern winter winds reduces its effectiveness. After I kept these cold frames going through the 2nd lettuce cycle, I dismantled them and spread the soil, compost, and mulch over adjacent garden beds.

Currently, I’m working on a new 2′ x 6′ cold frame against the south-facing wall of my house. Thus far, I’ve only put a sill plate into the concrete wall using masonry nails, with the rest of the frame still not started, but the basic design I have in my head is...

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[JDPriestly]

1. Building the cold frame next to the house will protect the plants from the wind, but

there is a downside. The house will most likely at some time of the day cast a shadow on the cold frame and the plants. The cold frame may get less sun if it is near the house.

[IrateCitizen]

2. Thanks for the feedback.

I understand what you're saying, but having checked out the solar angles I have throughout the year I'm pretty confident that it will receive a good amount of sunshine -- especially when the sun drops in the sky during the colder months. If I lose it to shade during the main part of the growing season, I'm not going to be put out -- that's when I'm relying on my garden beds.

[JDPriestly]

3. Good point.

I have seen boxes on wheels for planting. Could you build a cold-frame on wheels?

[IrateCitizen]

4. Yes and no.

If you heavily insulated the walls and floor, it could work. However, I think that this setup would create some significant problems. First, you have to deal with the weight of the soil (and water) and provide adequate structural support. Second, you lose the ability to have the plants draw upon the in-situ soil moisture, significantly increasing the watering requirements. Third, by elevating the cold frame, you lose the inherent insulating properties of the soil. The way that growers used to create hotbeds (with buried fresh manure used to generate the heat) was to make the growing surface at least a few inches lower than the soil outside the box.

For me, personally, I'm always looking for ways to do LESS work in my gardening and permaculture systems. So I'm trying to use rock infill outside the box to help capture water and solar heat gain, combined with a slightly depressed growing surface to aid in heat retention, in the hopes that it will make my early and late season growing virtually maintenance free except for harvesting.

[JDPriestly]

5. Good points. I guess it depends on your situation.

I have to place my planting box on a cement surface so the wheels appeal to me.