During the first couple months of the year I always get a little bored waiting for spring. I can’t start seeds until about the 3rd week of February. So, I think of other things that I can do in preparation for the season. This year I will be sterilizing some of my soil in my solar oven. Our desert climate has plenty of sunny days in the winter. We can reach temperatures of at least 250° F all year around.

I got this oven about 4 years ago and have since found many uses for it. While not all are on the topic of gardening, they share common themes of self-reliance and emergency preparedness (along with some coolness factor).

Soil Sterilization

solarOvenMy soil block recipe call for some good old sand. In New Mexico we have plenty to spare, but I don’t want to introduce weeds. I use the solar oven to nuke the seeds and bugs out of the soil. You need the soil to reach a temperature of 180. Be careful not to let the temperature go over 200. To do this I purposely set the oven off the solar axis (see below). You only need about 30 minutes at this temp to kill all the bad guys.

Different temperature ranges kill different kinds of bad guys (see source):
140° - 160° : Most weed seeds, All plant pharming bacteria, most plant viruses
157° - 178° : Soil Insects, worms, slugs, mold, nematodes
Winter & early Spring are good times to sterilize soil because with a pre-heated solar oven you can heat quickly and then take the soil outside will cool it quickly.

Other Solar Oven Uses

In general, the solar oven is great for anything that needs a temperature between 150 and 280 for a long period of time. You have to be somewhat flexible and somewhat available during the cooking period, but we have left food in the oven and gone to the store or church and come home to a perfectly cooked meal.

So here are my current uses of my solar oven:

Hint: Often food does not brown in a solar oven like a regular gas or electric range. We have to use another method to tell when food is "done"
  1. Baking Bread and Cakes – This is an easy one. They take a long time and can be done at a lower temperature (just takes a little longer). Make sure to clear the glass after about 45 minutes of the water droplets that condense.
  2. Purifying Water – Water at 50° C (122° F) will purify in one hour(source). Remember that the water has to be at this temperature for an hour, not just the oven. Don't count warm up time. Use a thermometer in the water.
  3. Soups – Another long cooking item that does really well in a solar oven. Make sure to give yourself an extra 20-30 minutes in case a cloud passes by and slows down the cooking.
  4. Camping – Go for a hike and the food is ready when you get back. Be careful for wind and rain though
  5. Baked Potatoes – Excellent baked potatoes. Don’t wrap in foil because that will reflect the heat. They still stay moist because of the sealed environment

I have tried making yogurt in the solar oven, but you have to angle a bit away from the sun to keep the right temp (110 – 115). Management of this for 8-12 hours is probably not worth it. You can do yogurt in the oven with just the oven light on and warming it for 1-2 minutes every 3-4 hours. Feel free to let us know what else you have tried with a solar oven and what has worked well. Although they typically cost $150-200, they are excellent as a backup cooking source and also keep the heat out of your home in the summer. Although I have not tried it myself, it is possible to make your own solar oven. You need reflective surfaces to focus the suns rays into a heat holding compartment. I have read of people painting brick black in a more permanent solar oven structure. The potential uses are endless!