Using tire sidewalls, the part left over from cutting the tires to use them as planters, had the downside of being heavy. They also cut back quite a bit of the light. Not that they didn't work. So we were looking at an alternative when I came up with this idea.
On the left about knee height is the old method using the tire sidewall to make the cover. The white material is ripped up garden wrap that has been stapled and glued down.
What I am placing is an "OctoCover" with the plastic wrapped around a circumference of 1 X 2 inch lumber. They are extremely light and need to be tied to the tire with three wire ties ( might use rubber cut from old bike tubes). This greatly increase the amount of sunlight entering the tire cold frames. The soil is still pretty wet and cold but yesterday the temperature two inches down was 18c. A couple of days of beautiful sunshine like were having and things should be drying up.
The reflective top tire ( the riser ) is achieved by gluing heavy duty aluminum wrap to the inside of the tires. They really increase the light in the tire. The black knob in the middle is the top of the 1/2 inch poly drip irrigation feed that is buried beneath all the tires. This year I am going to feed the water via a couple of 45 gallon drums painted black to heat the water a bit from it's cold spring temperatures.
Walking around in the garden is like wearing snowshoes made out of mud. We are going to be opening up a new gravel pit and will put down some geo-textile and gravel to take care of that situation. As you can see I have an extra pair of helper legs grafted on to help deal with the situation.