This section is from "The Horticulturist, And Journal Of Rural Art And Rural Taste", by P. Barry, A. J. Downing, J. Jay Smith, Peter B. Mead, F. W. Woodward, Henry T. Williams. Also available from Amazon: Horticulturist and Journal of Rural Art and Rural Taste.
Spring is again at hand, and with it come our preparations for forwarding and forcing to anticipate Nature by a few weeks or months.
I can offer little new in such matters except, perhaps, that, as our operations are conducted with a view to profit, and on a large scale, we flatter ourselves that in some respects our system is simpler and cheaper than that adopted in private practice, competition having the effect of drawing out all contrivances, so as to make our manner of working as profitable as possible.
In the raising of tender plants, such as tomato, egg, melon, or cucumber, there is often a great error committed in starting too early, as they can not be safely planted out in this district until the 20th or 25th of May. The 15th of March is much more preferable for starting the hot-bed than the 15th of February; and if the use of a green-house can be had by sowing in boxes there, there is no necessity for starting the hot-bed until the 10th or 15th of April, when the green-house plants that have been sown a month previous, in the green-house, may be planted in the frame.
Our manner of making hot-beds is different from that in general use in private gardens: whether the wood-work of the frame is stationary or portable, we invariably use a pit for the reception of the prepared hot manure. This pit is from 2 to 2 1/2 feet deep, 6 feet wide, and of any length required. The advantage of this over having the hot-bed built above the ground is, that it requires less heating material, and, being all under ground, is but little affected by the outside temperature. The manure being duly prepared by two or three turnings, the pit is filled up - packed moderately firm - to within 9 inches of the top of the boards, the sashes put on, and kept close to "draw up" the heat. As soon as the heat is found to be up in the frame - but not before - four or five inches of dry soil is regularly spread over the surface, in which is plunged a thermometer for a day or two, and when it indicates a temperature of 80 degrees, with a tendency to decline, the seed is sown or the seedlings planted, as the case may be. As the weather becomes warm, and the plants get vigorous, water is freely given, and air in warm, mild days.
The best protection from frost at night we find to be straw mats, made long enough to overlap the sash at each end six inches, a mat for a six-foot sash requiring to be something over seven feet long.
For raising our spring plants of cabbage, cauliflower, or lettuce, we use only cold frames; that is, frames on the surface of the ground without any heating material; these we usually start by the first week in March. Have the ground finely pulverized, and sow rather thin. By one month from the time of sowing we have fine, strong, hardy plants for planting in the open ground. Careful attention is necessary in giving abundance of air, and by covering up by straw mats at night so as entirely to exclude frost.
We have practiced this plan for some years past, and find it cheaper, requiring less attention, and producing much better plants than those raised in hot-beds.
[The above, from a gardener who works hot-beds and cold frames by the acre, is worthy of the reader's attention. We have no hesitation in giving a decided preference to hot-beds made below the surface, as being more lasting and economical. Hot-beds for raising plants for the open air are often overdone; they ought to be confined to such tender plants as the tomato, egg plant, etc., and for forcing an early crop of radishes, lettuce, cucumbers, etc. - Ed].