20 GARDEN PROJECT 
3. Cold frames and hot-beds. Since work with cold 
frames and hot-beds comes during the school season, 
it is by all means advisable to undertake this practical 
exercise at school. 
(a) Cold frames are devices for growing plants early 
or hardening them off for the field by making use of 
the heat of the sun through glass, without any founda- 
tion heating. They regulate heat and moisture and 
protect plants from heavy wind and dashing rain. 
The standard size of the cold frame sash is three 
by six feet, and the length of the cold frame will 
depend upon the number of sashes to be used. Make 
the frame six feet wide, eight inches high in front and 
twelve inches high at the back, of either one-inch or 
two-inch lumber. <A lean-to cold frame on the outside 
5. A CotD FRAME 
of a building may be made by nailing a two-by-four 
piece of lumber against the building and constructing 
the frame upon it. Good garden soil will furnish 
the seed bed for the plants to be grown in the cold 
frame. 
(b) For a permanent hot-bed, a pit about two 
