the outer shells of hotbed and cold-frame are identical, and can be made by any handy man. as all sashes are made in one size—namely, six by three—the boxes must correspond; to insure water running off and all the power of the sun being utilised, they must slope lengthways, the top end of a box being three or four inches higher than the bottom. the ordinary box or bed frame is made six feet long, three feet wide and fifteen inches high at the top end, sloping to twelve at the foot, and stands on the surface of the ground, but the plan we have adopted after several years’ experience is to dig a pit three feet deep, six feet two inches long and three feet two inches wide, and build the box twenty inches high at the top end, sloping to seventeen inches at the foot, and of course six feet long and three feet wide, which allows it to stand inside the dugout and five inches below the surface of the surrounding ground, so effectually preventing any cold air creeping in around the bottom. we use sound boards two inches thick for sides and ends and two-by-two studding for corner stays.
very well-made boxes and sashes, which fit exactly, are sold by several of the greenhouse builders for 106 about eight dollars. they are shipped knock-down to save express charges, but they are ready to bolt together. they come in the ordinary six-by-three size, for single beds, or in groups of from three to five, with light partitions for the sashes to rest upon. the five-section bed costs about twelve dollars, but will need five sashes, amounting to fifteen dollars, and the partitions, which i think are about one dollar a piece.
for convenience in bad weather, it is well to have the beds near the house, and, when possible, sheltered from the north and facing the south. fresh horse manure constitutes the heating power in a hotbed. we use solid droppings and dry leaves, about half and half. it is ripened in the manure-shed by being made into a heap about three feet high and three feet wide, thoroughly sprinkled with liquid manure. it is allowed to stand some weeks after mixing, then twice forked over, two weeks intervening. all the droppings should be well broken up and mixed with the leaves, and the entire mass repiled between each forking.
after the ripening process has been accomplished, it must be packed into the bottom of the hotbed to the depth of two and a half feet. it should be smoothly laid and well tramped into place. put in the sash, and within a few days the heat will rise to a hundred degrees or over. lift the sash slightly at one end, and wait until the temperature falls to about eighty-five degrees, then place about six inches 107 of rich, fibrous soil over the top. we manufacture our potting-mould several months before it is required, by taking the old heating material from spent beds and mixing it with an equal amount of soil from sod land and about one-third the quantity of clean, sharp sand. after thorough mixing, it is piled in a large heap and left exposed to the weather until required, or until late in the fall, when it is put into a shed and kept dry to prevent freezing, as potting-mould and covering for fresh hotbeds is often needed in the early spring. just before using, it is passed through a sieve to remove all lumps.
the first year, when there is no old bed to empty, good top-dressing or potting-mould can be made by cutting deep sods, shaking the earth from the roots and mixing it with an equal amount of old, well-rotted cow manure and about one quarter the amount of clean sand. it is imperative to prepare all such things in the fall. the outside of a hotbed should be banked up with rough stable manure and the sash covered at night with mats and shutters in extreme cold weather. old carpet or bags made of burlap and filled with cut hay will cost nothing except time and answer quite well. we use pads, for which all sorts of old clothes are utilised. then unbleached sheets large enough to cover the sash, side and ends, and reach well onto the ground, are used. the sheets are given two coats of oil, and so are impervious to rain or snow, and we think better than wooden shutters.
suppose you want to make your first venture with 108 winter salads, the first gathering for thanksgiving, and from then on until spring. start one bed the first week in october, sow three rows of lettuce seed five inches apart, sowing three different varieties, tennis-ball, boston market and big boston; two rows of curly cress (peppergrass) the same distance apart, and five days later, two rows of white mustard. eight or ten days later, prepare a second bed, so that the heat may have risen and decreased to about seventy-five by the time lettuce is large enough to transplant—about three weeks from the sowing of the seed. set out the seedlings eight inches apart each way in the new bed, and sow radish seed between the rows.
if you have enough frames, plant the three different varieties of lettuce in different beds. they will mature in the rotation named. between the rows of the boston market and the big boston, onion seeds may be sown. when selecting lettuce to transplant, choose the strong seedlings and from different parts of the rows, so that when the surplus plants are thinned out, the rest will be left to grow undisturbed.
the mustard and cress will be ready to cut in from seven to ten days after the mustard is sown. cut the cress with a pair of scissors a little above the soil and it will spring again and again. mustard must be sowed after each gathering, but as it only takes half the time to develop, it will be ready when the second crop of cress is. mustard should be allowed to grow more than an inch and a half above the ground. one 109 important thing to remember in running a succession of hotbed crops, is that the heating power of manure only lasts about seven weeks. beans, beets and swiss chard, and such hardy things, which require two months or more to mature, do not suffer through the decrease of heat, in fact, will do just as well, or better, in a spent hotbed or cold-frame, which is just a hotbed without any heating material. but if very cold weather sets in, bank up heavily around the sides and ends with fresh manure, to keep the cold from penetrating the bed-box, and using extra heavy mats over the sash at night.
eggplant, tomatoes and peppers should be started the last week in february, and celery, cabbage, cauliflower and brussels sprouts about the first of march. one bed should be devoted to onion seed (sown at the end of february), and seedlings can be pricked out into another bed or cold-frame when about two inches high, and will be strong bulbs to plant out in the garden in april. cucumbers, muskmelons and squash can all be started on sods in a hotbed, early in april, and will be sturdy plants by may 20th.
