Watering.—Since the glazed sash prevent the soil beneath them being moistened by natural means—that is, by rain or dew—it is necessary that means be provided for watering or irrigating the plants. This can be done by arranging pipes upon the surface of the ground or at a convenient height overhead, so as not to interfere with cultivation, from which water can be drawn to sprinkle the surface of the beds at desired intervals and as the plants may require. The work of watering should, however, be very carefully done. The same general precautions necessary for the care of plants in cold frames should be observed—that is, to do the watering in the morning on bright days only, when air can be admitted and when the sun will soon dry the moisture from the leaves of the plants. In this way much can be done to protect the plants from injury from such diseases as the damping-off fungus and mildew.
JAPANESE CLIMBING CUCUMBER NEARLY SIX FEET FROM THE GROUND
WELL-GROWN CUCUMBERS
Ventilation.—Besides the precautions to be observed in watering plants in cold frames, extreme care is necessary to give the plants sufficient air to keep them in a healthy condition. If the atmosphere is allowed to become close and very hot, the plants will be weakened and thus rendered more susceptible to the attacks of plant diseases.
Forcing Cucumbers Under Glass.—Forcing is a technical term used by gardeners to designate the growing of plants out of their normal season under an artificial environment. The cucumber is one of the few garden plants which lend themselves to this manner of cultivation in addition to their more extensive cultivation in the open ground. Under the stimulus of forcing work, two distinct types of cucumbers have been developed. These are recognized in the trade as the English type and the American type. The English type is purely a product of forcing-house conditions, as the climate of England is not congenial to the growth and development of the cucumber in the open. The American type of cucumber is primarily a product of field conditions, and the few varieties which have been developed to meet the requirements of the forcing house are simply modifications of the existing field or outdoor forms. The English type of cucumber is a long, cylindrical, uniformly green fruit, with few seeds and a very fleshy seed cavity; in fact, the normal seed cavity of the forced cucumber is almost entirely wanting. The triangular shape characteristic of the normal outdoor cucumber has been lost, and the cylindrical outline almost perfected. There is considerable difference in the size and length of the various English varieties of cucumbers. The American type of cucumber is primarily grown in the field, the product to be used either for pickling or for slicing. Forcing cucumbers in America is confined to those varieties which produce large fruits suitable for slicing. Only three or four of the better and larger field varieties are adapted to this purpose. Notable among these is the White Spine, the Arlington White Spine being the variety which has been especially developed for forcing. The Long Green, or a modification of it, is also sometimes used, but aside from these two varieties there are few that ever find their way into the forcing house. Such varieties as the Boston Pickling, Chicago Pickling, and the cluster varieties in general are not adapted to forcing purposes. The forcing of cucumbers presupposes that an adequate forcing house or greenhouse is at hand for such work. The chief desideratum in a forcing house for cucumbers is a maximum amount of light, sufficient headroom, and adequate radiation to maintain a temperature varying from 65° to 85° F. The amount of radiation will, of course, depend upon the style of heating employed, whether steam or hot water, and upon the location of the greenhouse, whether at the north or the south; the outside temperature determining to a considerable extent the amount of radiation required in the house to maintain a given degree of heat.
Propagation.—There are a number of methods of propagation followed by successful cucumber growers, all of which have some advantages. Three of the more common practices are as follows: (1) To plant the seeds of cucumbers in the soil of the bench where the plants are to grow and mature; (2) to plant the seeds of the cucumbers in 3-inch or 4-inch pots filled about half full of soil and after the seeds have germinated and the hypocotyl or stem of the seedling has elongated to fill the pots well up to the seed leaves with soil; and (3) to plant the seeds in cups similar to those used for harvesting strawberries, except that the cups for this purpose are usually made of Georgia pine. In the first case, where the seeds are planted directly in the soil on the benches, cucumbers are usually employed as a crop to follow lettuce, seeds being planted in the lettuce benches before the crop is entirely removed, heads of lettuce being taken out at proper distances to allow for the correct spacing of the cucumber plants, and the seeds of cucumbers planted in the areas so left. In the other two cases the rearing of the plants for forcing purposes can be carried on in a small house especially designed for this purpose or in a general propagating house, thus obviating the necessity of heating and maintaining normal conditions in the growing house during the period previous to which the plants begin to run.