In constructing the hotbed there are two methods used; either by 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 former 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 side, a foot and a half deep, and as long as the number of sash to be used demands—a cord of manure thus furnishing 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 or built 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, 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 in. 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 vegetable 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.
The coldframe is constructed practically as in the hotbed, except that if manure is used at all it is for the purpose of enriching the soil where lettuce, radishes, cucumbers or other crops are to be grown to maturity in it.
If one can put up even a very small frame greenhouse, it will be a splendid investment both for profit and for pleasure. The cost is lower than is generally imagined, where one is content with a home-made structure. Look into it.
PREPARING THE SOIL
All this may seem like a lot of trouble to go to for such a small thing as a packet of seed. In reality it is not nearly so much trouble as it sounds, and then, too, this is for the first season only, a well built frame lasting for years—forever, if you want to take a little more time and make it of concrete instead of boards.
But now that the frame is made, how to use it is the next question.
The first consideration must be the soil. It should be rich, light, friable. There are some garden loams that will do well just as taken up, but as a rule better results will be obtained where the soil is made up specially as follows: rotted sods two parts, old rotted manure one part, and enough coarse sand added to make the mixture fine and crumbly, so that, even when moist, it will fall apart when pressed into a ball in the hand. Such soil is best prepared by cutting out sod, in the summer, where the grass is green and thick, indicating a rich soil. Along old fences or the roadside where the wash has settled will be good places to get limited quantities. Those should be cut with considerable soil and stacked, grassy sides together, in layers in a compost pile. If the season proves very dry, occasionally soak the heap through. In late fall put in the cellar, or wherever solid freezing will not take place, enough to serve for spring work under glass. The amount can readily be calculated; soil for three sash, four inches deep, for instance, would take eighteen feet or a pile three feet square and two feet high. The fine manure (and sand, if necessary) may be added in the fall or when using in the spring. Here again it may seem to the amateur that unnecessary pains are being taken. I can but repeat what has been suggested all through this book, that it will require but little more work to do the thing the best way as long as one is doing it at all, and the results will be not only better, but practically certain—and that is a tremendously important point about all gardening operations.