518 FORCING THE ASPARAGUS, SEA-KALE, &C. 



water; and the more water the sea- kale receives in this way, the more 

 tender it becomes. The roots are placed in this fermenting matter as thick 

 as they will stand, merely flooding in some fine old tan or old rich soil with 

 water, to fill the crevices between the roots completely. The surface of the 

 crowns, when so placed, is a foot, or nearly so, below the floor line ; and, 

 when planted, a row of trusses of straw is laid side by side over the whole, 

 to shut in the steam, and keep it completely dark, which is one of the main 

 points ; and, with the straw and the shutters, this is completely effected. In 

 the same house Mr. Errington produces a continual supply of chiccory, 

 rhubarb, and other articles, by the same system. (G. M. 1841, p. 270.) 



No vegetable is more easily or cheaply forced than sea-kale, whether in the 

 open air in beds or drills, or by covering the plants with pots (fig. 58, in p. 143) 

 or boxes to be surrounded by hot dung ; or by taking up the plants and potting 

 them, and placing them in cellars, frames, or pits, or on a bed of heated ma- 

 terials. A temperature of from 40 to 45 degrees will excite vegetation, after 

 which it may be raised to 50 or 55 degrees. Great care must be taken never 

 to exceed 55 degrees. Plants of sea-kale in the open ground may be forced 

 every year ; but much the cheapest mode is to take up the roots and force 

 on beds heated artificially. 



1098. Rhubarb and Chiccory. What has been said of sea-kale, in the 

 preceding paragraph, will apply equally to rhubarb and chiccory. They 

 may both be forced in the open ground by trenches filled with hot dung, or 

 by pots or boxes placed over them, and surrounded by that material ; or, 

 what is by far the most economical mode, the plants may be taken up and 

 potted, and placed in a cellar ; or, like the sea-kale, they may be planted 

 close together on a bed of material heated artificially, or laid side by side in 

 the floor of a vinery, or between the flue and wall, and covered with 

 tan, peat, or leaf-mould. The rhubarb should be grown at least two years 

 from the seed, in the same manner as the sea-kale, before being taken up 

 for forcing ; but the chiccory may be sown the same year. The leaves of 

 the chiccory require to be blanched, and therefore it ought always to be 

 forced in the dark ; but as most people prefer the rhubarb only partially 

 blanched, a certain degree of light may be admitted. In Belgium the 

 roots of chiccory are taken up on the approach of winter, and stacked in 

 cellars in alternate layers of sand, so as to form ridges with the crowns of the 

 plants on the surface of the ridge. Here, if the temperature is a few degrees 

 above the freezing point, the crowns soon send out leaves in such abundance 

 as to afford an ample supply of salad during the whole winter. (See 

 Lippold, in G. M. for 1836, p. 250.) 



1099. Forcing other roots. The common dandelion (Leontodon Taraxa- 

 cum, L.) affords a salad in all respects equal to that of the chiccory, and may 

 be similarly treated. Hamburg parsley, the common parsley, burnet, fennel, 

 wild spinach (Chenopodium Bonus Henricus, Z,.), wild beet, for the leaves 

 as spinach, and the common turnip -for the leaves as greens, and various 

 other plants having fleshy roots, and of which the foliage or leaf- stalks are 

 used in salads or cookery, may be forced on the same principle as asparagus, 

 sea-kale, &c. ; the practice being founded on the physiological fact first 

 explained to gardeners by Mr. Knight, viz., that " the root of every perennial 

 herbaceous plant contains within itself, during winter, all the organisable 

 matter which it expends in the spring in the formation of its first 

 foliage and flower-stems ; and that it requires neither food nor light to 



