ON PLANT PROPAGATION. 947 



as stable sweepings, leaves, spent hops, &c, which are chiefly used 

 in the preparation of hot-beds. The depths of the beds may vary 

 from 2ft. to 3ft., according 

 to the amount of heat re- 

 quired. Once the frames 

 (Fig. 615) are fixed on, 

 another bed of a couple 

 of inches of suitable soil 

 or fibre is laid on, and 

 the whole is covered with 

 lights. At first the heat Fig. 615.— Two-light Frame. 



increases so rapidly that 



it is advisable to wait a few days until the thermometer has 

 dropped to a safe heat (about 7odeg.). Seeds sown in pans 

 or pots may then easily be started in these frames, and they may 

 also in many instances be sown directly on the beds ; indeed, 

 this method is often adopted for early vegetables. These hot- 

 beds under frames are very much used on the Continent. 



Pricking-off, &c. — Pricking-off is a kind of transplantation, 

 which is required by nearly every seedling, especially those sown 

 in a very limited space, as in pans, pots, &c. It is really 

 surprising how thickly some young seedlings will come ; they 

 then require to be thinned, and that is the time to do the 

 pricking-off. Thinning is the first necessity for the welfare of 

 the whole patch ; if this is not done, the young plants will grow 

 up weakly, and will soon be exhausted. The operation must 

 always be done with great care, to avoid breaking any roots or 

 otherwise injuring the young seedlings. Some kinds of plants 

 require several prickings-off to enable them to root more freely. 

 The soil or compost used for this subsequent pricking-off must be 

 more substantial than that in which the seedlings were first sown. 



It is a difficult matter to describe all the ins and outs in 

 regard to seedlings. All receptacles, frames, or outside beds in 

 which seedlings are to be sown must be clean, so as to prevent 

 them from coming in contact with any deleterious matter. 

 Inside seedlings must be protected from the direct rays of the 

 sun, and must not be allowed to become either too dry or too 

 wet. The surface of the soil in which seeds are sown may be 

 covered with a thin layer of silver-sand, so as to protect them 

 from cryptogamous vegetation. No weeds or mosses of any kind 

 ' must be allowed to get a footing. The temperature should also be 

 observed ; it can gradually be increased until the plants begin to 

 grow. A great point is to place the pans or boxes as near to the 

 glass as possible as soon as the seedlings develop their first leaves. 



Division. 



Next in importance to propagation by seeds conies the 

 present method, by which a great many plants are propagated. 



3 p 2 



