Forcing

Forcing, in Gardening, is a term used to designate a process in which artificial heat is applied so that flowers, fruits, or other products of plants are obtained at a date or season other than that at which they may be had in the ordinary course of culture. Thus, for example, kinds of grapes which by the simple influence of the heat of the sun in a vinery do not ripen till September or October are induced by forcing to ripen in March or later, according to the period the process is commenced; and strawberries, which ripen in the open air in Britain variously from June to September, in the forcing-house yield their fruit from February onwards. Conducted, as the system is, during the short days of the year, the chief obstacle the gardener has to contend with is diminished light. This in the case of forcing fruits taxes his skill to the utmost, because abundant light is essential both to the proper fertilising of the flowers and to the perfecting of the fruit. Some vegetables and salads and many flowers are, however, more successfully forced in the dark than in light. Rhubarb, sea-kale, mushrooms, lily of the valley, lilac, are all forced in greater or less darkness in order the better to develop their individual perfections. The remarkable purity of the colour of the flowers of the last two, as seen in the shops in December and January, is due to this circumstance; and the result will appear the more striking to the uninitiated when it is stated that a purple variety of lilac is preferred to a white one for forcing, because it not only comes out of the process a purer white, but with greater substance than the latter. Forcing in its application to various plants—especially flowering plants—has greatly extended during the last twenty years, and is still extending. It may be regarded as the greatest triumph of horticultural art, because it renders possible the enjoyment of nature's summer bounties in all their freshness, lusciousness, and beauty in winter. See GARDENING.