12 THE BOOK OF THE GREENHOUSE 



allow of the soil being in that nice condition known 

 as neither wet nor dry, and the new soil should be 

 in about the same condition, i.e., damp enough to 

 bind together when rammed, yet not so wet as to 

 become pasty with ramming. Sufficient new soil should 

 be put into the new pot to elevate the ball of soil 

 and roots attached to the plant, which has been 

 previously freed from the old drainage material, high 

 enough to prevent any portion of the stem which has 

 hitherto been uncovered from becoming buried in the 

 process of potting, as to bury the " collars" of these 

 plants is generally injurious and often fatal to them. 

 Some of the more delicate species, indeed, do better 

 and live longer when the " collar" is left slightly higher 

 than the surrounding soil. To complete the potting 

 in a workmanlike way the old ball of soil should be 

 placed exactly centrally, so that there may be an equal 

 distribution of new soil all round it, and this should be 

 put in a little at a time, each successive layer being well 

 rammed home, leaving no crevices, until the potting is 

 complete. Potting should take place at a time when 

 the roots have resumed activity after a slight rest. 

 This will in most cases be when the new growth, made 

 after flowering, has been perceptible for two or three 

 weeks. As the period of growth varies according to 

 the different species and their time of flowering, no 

 particular period can be mentioned, except that it is 

 some time during spring or early summer. 



Most of the plants in this section are essentially what 

 are known as cool greenhouse plants and are very im- 

 patient of fire heat at any time. This, combined with 

 their inability to withstand frost, renders their cultiva- 

 tion a matter of careful watching and solicitude on the 

 part of the grower. In the winter, the temperature of 

 the house may safely be allowed to fall within a very 

 few degrees of freezing point, when the outside tempera- 



