644 KADICACEOUS ESCULENTS. 



happens when potatoes are laid between layers of earth in boxes. {Ibid. 

 p. 315.) The same thing has been effected by II. Taplin, who selects the 

 largest potatoes he can find in spring, continues rubbing off the sprouts as 

 fast as they appear till the month of August, when he prepares a bed of light 

 soil, about six inches thick, in a dry, warm shed. On this bed he places 

 his potatoes whole, and nearly close to each other, covering them with light 

 soil, four inches deep, giving it a moderate watering, and letting the bed 

 remain in that state till it is time to cover it over, in order to protect it 

 from frost. On examining the bed in December, he found an abundant crop 

 of potatoes, without the least appearance of haulm or outward shoot from 

 the parent root. (Gard. Chron. 1841, p. 182). See also 1101. 



1414. Selecting and preparing the sets. As the buds at the top end of the 

 tuber, like those on the points of shoots of trees, always vegetate first, these 

 are chosen for sets for an early crop, and they are found in the case of the 

 Rufford kidney to produce a crop nearly a fortnight earlier than sets taken 

 from the root end of the tuber, where the starch being more concentrated, 

 requires a longer period to be converted into mucilage (552). For a main 

 crop the point of the tuber should be rejected whenever it contains a num- 

 ber of small buds, because these produce an equal number of weak stems, 

 which, as shown above (1306), are far inferior in productiveness to one good 

 stem ; and the root end ought to be rejected, because the buds there, espe- 

 cially when the potato is over-ripened, sometimes do not vegetate. Early 

 potatoes intended for being cut into sets are found to keep better and sprout 

 earlier when they are taken up before they are ripe, just when the outer 

 skin peels off, and before the stalk or stem begins to wither, and exposed to 

 the direct influence of the sun in any dry surface, till they become green. 

 This will require a month or six weeks, when they become quite green 

 and soft, as if frosted, and often much shrivelled. They are then put 

 away in a cellar or pit, where they remain dry and cool till February, 

 when they will be found sprouted and fit to cut into sets, and plant at 

 once. 



1415. Greening potatoes for sets, is practised as above (1414), stated with 

 a view towards forwarding the crop; but u why it does so, appears to be imper- 

 fectly understood, even by those who practise it. It is well known that 

 tubers are not solely formed on the underground part of the stem ; they 

 are also formed upon the stem above ground in many varieties, and these 

 formations are of course green. Though formed at the same time as those 

 below, or later, yet they sprout directly, in the same manner, even in the 

 case of late varieties, the underground tubers of which do not vegetate till 

 the following spring. When, however, an underground tuber is exposed to 

 light, it becomes green, arid thereby is assimilated to the nature of the tuber 

 produced above ground, and like it disposed to sprout earlier than those not 

 subjected to the influence of light. It is not, however, necessary to green 

 the sets for a general crop, for if planted in time they come up early enough 

 to be safe from spring frosts without previous exposure, for the purpose of 

 greening ; but in the case of early plantations (1408), with protection if 

 necessary, greening may be of some advantage ; and in the method of 

 retarding the sets so as only to plant them in July for a late young crop, it 

 is unavoidable, for the tubers would either grow too much or rot, if they 

 were not spread out in a dry cool situation, and consequently one unfavour- 

 able for growth. Instead of greening the tubers when taken up, and 



