(and other devices)

We built our 'solar pod' in 1996 based on the book Solar Gardening by Leandre and Gretchen Poisson (a book with many ideas for season extending besides the solar pod). It has since become an integral component of our garden. This 4'x8' mini-greenhouse is built primarily of exterior grade plywood, 2"x4"s, and .04 inch thick fiberglass glazing. 

Click Pictures to Enlarge

On the left is the solar pod in its closed position. It sits on a cedar 2"x8" base that can be extended for taller crops - such as peppers, by adding another 2"x8" box. The covering is comprised of two layers of 40 mil fiberglass with angel-hair fiberglass in between. These photos were taken on March 4, 2004. At this time, the spinach had already been harvested twice,  with the first harvest used for a Valentines dinner party in our sunroom.

We have experimented with various plants in our solar pod, discovering our best results with spinach and peppers. We discovered that if we plant spinach in this pod in November, by March we have a beautiful crop of spinach that can be harvested for nearly 4 months. In our climate, small spinach plants can remain dormant during December and January in an unheated but insulated cold frame. By February, there is enough light and heat to stimulate growth in these young plants, such that by late February, the leaves are large enough to harvest. In our northern Illinois climate, soil temperature is too low to plant spinach until around mid April, so using the solar pod over winter gives us a very early harvest. However, the best thing about planting in this manner is how daylight length will work to our advantage.  An unprotected, mid-April planting of spinach will produce until late June, at which time it is no longer harvestable because it bolts and goes to seed. The tendency to bolt is caused by long daylight hours as well as by high temperatures. These two criteria  apply as well to spinach over-wintered in the solar pod, meaning the spinach in the solar pod will also bolt in late June. The result is that we can harvest spinach at least two months longer from the solar pod than from the unprotected planting. During the first year we planted spinach in this manner, we harvested 2-3 bushels of spinach out of this 4'x8' space over the months of March - June. This approach represents another permaculture application in this case, working with growing cycles of nature to maximize abundance.

The photo at left was taken in early June. The spinach plants were preparing to go to seed, but by this time had produced a significant volume of harvestable leaves. Unlike most plants in our climate, these spinach plants were able to utilize sunlight during the late winter - early spring period when it is usually too cold for plant growth.

The photo on the right was taken on November 6, 2004 - well past our normal early October freeze date. The pimenton peppers in the 2 gallon bucket were perfect, with no insect or frost damage. As you can see, the plants were still lush and productive even though by then we had a few freezing nights and the day length was rapidly waning. The short day length reduced the plant's ability to produce further fruit, meaning this was the last pepper harvest, even though the plants were still growing. Notice in this picture the dill and endive outside the wooden box. These plants sprouted on their own from seed dropped by an earlier crop. On the other side of the solar pod was a spinach and lettuce patch that had also sprouted on its own. In these volunteer patches, only minor weeding was required to produce a healthy salad crop through the end of November when cold and inadequate light eventually drove the plants dormant. Letting plants grow where they wish in this manner is another application of permaculture - in this case, the principle is - don't do any more work than is necessary. 

We also utilize water teepees for season extending. These 'teepees' are constructed of flexible plastic similar in design to the popsicle containers you fill and then freeze. This simple design, once its tubes are filled with water, moderates the temperature inside the teepee and allows transplanting seedlings at least a month earlier than would otherwise be possible. We use them to plant broccoli and cabbage in late March, then we move them to peppers, eggplants, and tomatoes a month later. This is especially useful for peppers and eggplants since these plants need long growing seasons to produce well (their lifespan in tropical climates actually exceeds a year). Not only does the teepee protect the plants from temperature swings, but also from our sometimes strong spring winds, and in the case of eggplants, keeps away the flea beetles that are very damaging. 

The water teepees in the photo on the left are covering a patch of peppers and eggplants after having been moved from the broccoli and cabbage plants growing in the foreground. Situating these plants next to one another minimized the effort to move the water filled teepees.

The photo on the right depicts a makeshift greenhouse Mark created using Mylar film given to him by his brother Brent. As you can see, this amount of protection was effective in protecting a young lettuce crop, getting it off to a good start long before lettuce could be planted without protection. Because it was built from old lumber and free mylar, it cost practically nothing.