How to Build a Hot House for Plants

In the past, hot houses required creating a building that either was attached to another building such as a house, or was a free-standing building itself.

A hot house may consist of an outdoor building or be a box on a windowsill.A hot house may consist of an outdoor building or be a box on a windowsill.
With simple technology, even apartment dwellers now may create a simple hot house. On the surface, the hot house looks like a greenhouse, but instead of adding supplemental heat, passive solar energy keeps this structure warm. Aluminum-foil covered walls create a reflective surface that helps intensify the sun's rays, which helps warm the indoor hot house. The dark-colored soil used in this project acts as a solar collector that absorbs heat from the sun during the day and releases it at night.

Pick what is the front of the hot house and measure 4 inches up from the bottom of one end of the box; mark this spot. Continue placing these marks all the way across this side. Use a ruler to connect these marks and create a straight line.

Continue the 4-inch mark on each side of the box. Going diagonal from this mark, draw a line that goes up to the opposite corner on that side. Repeat the process for the other side.

Cut along the lines drawn on the front and sides of the box.

Measure and cut three sheets of aluminum foil that are 12-by-16 inches.

Hot glue does not hold up in a hot house.

Glue the aluminum foil on the inside of the back wall with the shiny side up. Repeat the process on each side. Once the foil is glued, trim away any excess.

Flat-head thumbtacks work better than raised ones for this project.

Cut the garbage bag down both sides and across the bottom. Place one of the sheets inside the box and push it down into the bottom. Secure the plastic bag to the box with thumbtacks.

Make sure soil level is equal all the way across the surface.

Pour a 3-inch layer of potting soil into the bottom of the box. Plant your seeds of choice in the soil.

Gently water the seeds. Tightly cover the box with the other plastic garbage bag sheet. Secure the plastic sheet to the box with clothespins, then place the box in a sunny, south-facing window.

Things You Will Need

  • Cardboard box, 12-by-12-by-16 inches
  • Ruler
  • Marker
  • Scissors
  • Roll of aluminum foil
  • Super glue
  • 11-gallon clear plastic garbage bag, 1.75 mil thick
  • Thumbtacks
  • Bag of all-purpose potting soil
  • Seeds such as Bibb lettuce and radish
  • Package of clothespins

About the Author

Mindy McIntosh-Shetter has been writing since 2010. Her work appears on various websites and blogs. Her educational background includes a Bachelor of Science in agriculture education with minors in biology and natural resources from Purdue University. She is pursuing a master's degree in environmental education and urban planning from the University of Louisville.