Seedling House

Build this seedling house from inexpensive materials available at any home center. The shop light will provide the warmth needed for germination, and the light for the seedlings to grow. Regulate the temperature by adjusting the size of the air hole on top. Raise the light as the seedlings grow, and to make watering easy.


  • One Sheet 4' x 8' Foil-Faced Rigid Insulation Board, 1/2" thick
  • One 4' Fluorescent Shop Light with two 40W bulbs
  • Two 7' sections small chain
  • Grounded Extension Cord
  • Outdoor Thermometer
  • Duct Tape
  • Wire Coat Hangers


  • Sharp knife
  • Straight edge or yard stick
  • Tape Measure
  • Pliers

(click for enlarged view)


Cut the foam insulation board to the dimensions shown. To do this, score the board through the foil along a straight line and bend back to break; then cut the foil on the other side. It will help later if measurements are precise. Do this at the home center so that the pieces will fit in a car.

Start with the 18" wide base on a workbench. Use small pieces of tape to locate a 21" side on top of the base and a 22" end on the workbench butted up against the base and side. Put the shinier sides inside. Repeat with the other side and end. When the four sides are tacked in place, seal the seams with duct tape. Cut two round holes in the top at locations to match the chain spacing on the shop light. Also cut a rectangular hole slightly smaller than the piece that covers it.

Rest the shop light inside the seedling house and attach the chains and extension cord to it. Lead the chains and extension cord through the holes in the top, then put the top in place. Bend hooks from wire coat hangers and suspend them from joists in the ceiling. Then raise the shop light by the chains and hang them on the hooks.

Mount the thermometer inside the seedling house, within view of the hole in the top. Place planted flats on the bottom. The light should be left on 24 hours a day until the seedlings emerge, and the temperature kept at 70°F to 90°F, depending on the type of seed. Young seedlings generally require about 16 hours of light per day and lower temperatures. Disconnect the extension cord and raise the shop light out of the seedling house when watering.

Copyright © 1997 A. Peter Allan. All Rights Reserved.