Gardening Indoors and Under Glass / A Practical Guide to the Planting, Care and Propagation of House Plants, and to the Construction and Management of Hotbed, Coldframe and Small Greenhouse

by F. F. Rockwell

The simplest form of home glass is the coldframe. The simplest hothouse is the manure heated coldframe or hotbed.

The following directions for making the frames and preparing the soil for them are taken from the author's Home Vegetable Gardening.

For the ordinary garden, all the plants needed may be started successfully in hotbeds and coldframes. The person who has had no experience with these has usually an exaggerated idea of their cost and of the skill required to manage them. The skill is not as much a matter of expert knowledge as of careful regular care, daily. Only a few minutes a day, but every day. The cost need be but little, especially if one is a bit handy with tools. The sash which serves for the cover, and is removable, is the important part of the structure. Sash may be had, ready glazed and painted, at from $2.50 to $3.50 each, and with care they will last ten or even twenty years, so you can see at once that not a very big increase in the yield of your garden will be required to pay interest on the investment. Or you can buy the sash unglazed, at a proportionately lower price, and put the glass in yourself, if you prefer to spend a little more time and less money. However, if you are not familiar with the work, and want only a few sash, I would advise purchasing the finished article. In size they are three feet by six.

Frames upon which to put the sash covering may also be bought complete, but here there is a chance to save money by constructing your own frames—the materials required being 2 x 4 inch lumber for posts, and inch-boards; or better, if you can easily procure them, plank 2 x 12 inches.

So far as these materials go the hotbed and coldframe are alike. The difference is that while the coldframe depends for its warmth upon catching and holding the heat of the sun's rays, the hotbed is artificially heated by fermenting manure, or in rare instances, by hot water or steam pipes.

In constructing the hotbed there are two methods used; either placing the frames on top of the manure heap or by putting the manure within the frames. The first method has the advantage of permitting the hotbed to be made upon frozen ground, when required in the spring. The latter, which is the better, must be built before the ground freezes, but is more economical of manure. The manure in either case should be that of grain-fed horses, and if a small amount of straw bedding, or leaves—not more, however, than one-third of the latter—be mixed among it, so much the better. Get this manure several days ahead of the time wanted for use and prepare by stacking in a compact, tramped down heap. Turn it over after three or four days, and re-stack, being careful to put the manure from the top and sides of the pile now on the inside.

Having now ready the heating apparatus and the superstructure of our miniature greenhouse, the building of it is a very simple matter. If the ground is frozen, spread the manure in a low, flat heap nine or ten feet on each side, a foot and a half deep, and as long as the number of sash to be used demands. A cord of manure thus furnishes a bed for about three sash, not counting for the ends of the string or row. This heap should be well trodden down and upon it should be placed the box or frame upon which the sash are to rest. In using this method it will be more convenient to have the frame made up beforehand and ready to place upon the manure, as shown in one of the illustrations. This should be at least twelve inches high at the front and some half a foot higher at the back. Fill in with at least four inches—better six—of good garden soil containing plenty of humus so that it may allow water to soak through readily.

The other method is to construct the frames on the ground before severe freezing, and in this case the front should be at least twenty-four inches high, part of which—not more than half—may be below the ground level. The 2 x 12 inch planks, when used, are handled as follows: stakes are driven in to support the back plank some two or three inches above the ground,—which should, of course, be level. The front plank is sunk two or three inches into the ground and held upright by stakes on the outside, nailed on. Remove enough dirt from inside the frame to bank up the planks about halfway on the outside. When this banking has frozen to a depth of two or three inches, cover with rough manure or litter to keep frost from striking through. The manure for heating should be prepared as above and put in to the depth of a foot, trodden down, first removing four to six inches of soil to be put back on top of the manure,—a cord of the latter, in this case, serving seven sashes. The vegetables to be grown, and the season and climate, will determine the depth of manure required—it will be from one to two feet,—the latter depth seldom being necessary.

It must not be overlooked that this manure, when spent for heating purposes, is still as good as ever to enrich the garden, so that the expense of putting it in and removing it from the frames is all that you can fairly charge up against your experiment with hotbeds, if you are interested to know whether they really pay.

The exposure for the hotbeds should be where the sun will strike most directly and where they will be sheltered from the north. Put up a fence of rough boards, five or six feet high, or place the frames south of some building.