Re: [gardeners] Seed Starting Box

Martha Brown (
Mon, 4 Jan 1999 00:55:25 -0600

The Feb 1999 National Gardening Magazine has instructions for a heated box
for starting seeds on page 28.
	"Build an  8" high X 24" X 48" box from 1/2" plywood.  Insulate the
interior sides of box with 1" blueboard or plastic foam.  Mount 4 outdoor
light sockets evenly spaced in bottom of the box connect in serial together
with electric cord exiting through hole in one side.  Use 40 watt bulbs. 
For the top cut a piece of metal sheeting to fit to outside edges.  paint
underside of metal black to retain heat from bulbs.  Fasten metal securely
to box with L brackets.  With lights turned on 24 hours a day pots of
seedlings placed on top stay between 70* and 75*F, even in unheated
basement.  Place thermometer on metal sheet,  if temp goes above 75* turn
bulbs off a few hours.  Be sure to place pots in a plastic tray and remove
from the top of box to water to avoid getting water in the box & short
circuiting light fixtures.

Hope this helps.

M Brown
NW Oklahoma, USA
USDA Zone 6b,  Sunset Zone 35

: From: William McKay <>
: To:
: Subject: [gardeners] Seed Starting Box
: Date: Sunday, January 03, 1999 9:43 PM
: I want to build something to get bottom heat to start seedlings but am 
: too frugal to purchase a heat pad.  I remember long ago reading about 
: building a box heated with regular incandescant light bulbs, but could 
: find nothing during a trip to the library today.  I think I have all the 
: necessary parts hanging around:  pine, old porcelain light bulb sockets, 
: rigid insulation, plexiglass, etc.  However, I dont remember the 
: specifics.  I am thinking of making something large enough to hold two 
: ten-twenty trays (@ 400 square inches).  
: Has anyone built one of these?  If so, do you have any tips?  E.g., how 
: many bulbs would one use and what size?  Is 7 1/2 inches deep enough 
: (that is the widest pine I have, though I suppose I could glue up some 
: if I had to).  
: Bill McKay in E. Mass
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