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.
The seed may be sowed the last week in September, in the same way as above stated. In all latitudes where the frost is severe, these plants will require some winter protection. When they have grown three or four leaves, they may be planted four inches apart, in a box frame, and covered with glass sashes or shutters. The former is much the best; but will need to be covered with straw mats or other such material during extreme cold; the outsides, also, ought to be banked up with earth or litter, to keep out the frost. Give air at all favorable opportunities, remove the covers entirely in mild weather, but shut up and cover when there is frost. Never give water to these young plants during winter, but endeavor to keep dry and cool; this will prevent them from decaying in the "shank," a disease that is very common when there is an excess of moisture. If at any time they become thoroughly frozen, let them thaw in the dark, and afterwards let in air and light in abundance whenever the temperature is above 32°, and never leave the glasses shut when the sun shines on them. Many persons do not succeed in wintering young cauliflower plants, and principally from the neglect of the precautions here laid down.
When the fall sowing has not been attended to, a slight hotbed may be made in January as follows: Mark out on the ground, one foot larger on each side than the size of the frame, excavate one foot deep, build up evenly and somewhat solid, to the height of three feet, with hot stable manure in the earlier stage of decomposition, upon this place the frame and glasses immediately, and, when the heat has begun to subside a little, cover over with five inches of friable loam, and in this sow the seeds. Be careful to tilt up the sashes behind whenever the temperature inside rises over 50°. This will allow the steam to escape, and secure a wholesome atmosphere. When the seed-leaves are above ground, admit air more or less as opportunity occurs, but maintain sufficient heat to keep up a healthful progress, and increase the opening as growth expands. The object now is to get short and stocky plants, which never can be obtained without a free admission of air and light. The frost must, however, be guarded against, for in this state they will not bear it, nor yet until they have been gradually hardened off.
They should, also, be taken up when the first rough leaf is formed, and pricked out into the same bed, three inches apart, for the purpose of increasing the small fibrous roots and assisting the above desideratum. This last-described process is only a " makeshift," and ought never to be resorted to when winter-kept plants can be got, as these latter are always more hardy, and generally bring the finest heads.
To obtain a first early crop for the kitchen, it is necessary to make up a similar hotbed to the one above specified, about the middle of February, of any size, according to the quantity required or convenience of glasses at hand. In this case, there should be nine inches to one foot of rich mould introduced, plant out eighteen inches apart, keep close for a few days, afterwards give air freely, shot np at night, and cover to keep out frost; water as occasion requires, and take advautage of any warm showers that may occur.