Solar-Heated Greenhouses for Growing

Greenhouses give gardeners a place to grow and winter seedlings and protect tropical plants from the cold. A winter greenhouse can also provide fresh produce and herbs all year-round. However, heating a greenhouse can often negate any savings from growing your own food. Changing that fact means harnessing the sun's heat for your use. Solar heating your greenhouse is relatively simple, though it requires some heavy lifting and research.

• 1

  Stand inside your greenhouse with a compass, turning it until you find the north wall. This wall is directly opposite the south side of your greenhouse, the side that gets the most sun. You'll place your solar heat on the north wall so it can absorb the sun's heat through the south wall and reflect it into the greenhouse.

• 2

  Measure the height and width of your greenhouse's north wall. Measure the height and width of your 5 gallon buckets, also. Divide the width of the wall by width of your buckets and the height of the wall by the height of the buckets to find out how many you need. For instance, if your greenhouse wall is 9 feet high and 20 feet wide and your buckets are 3 feet high and 2 feet wide, you'll need 10 columns of 3 buckets or 30 buckets.

• 3

  Spray-paint all of your buckets and their lids black or another very dark color. Forest green complements a greenhouse and absorbs plenty of heat. If you need more than one coat, let the buckets dry for two hours between coats. Let the final coat dry overnight.

• 4

  Fill each of your buckets to about an inch below the rim with water from a garden hose. Snap the lids on tightly and stack the buckets in columns against the north wall of your greenhouse. The sun will warm the buckets and the water inside during the day. The buckets will release their warmth at night, keeping the temperature warm and steady.