59 



THE GREEN-HOUSE. 



laying the turfs in a heap to rot and moulder into 

 earth. This they will require several years to do ; 

 but in the mean while a portion of mould may be 

 obtained whenever it is wanted, by turning the turfs 

 and sifting the fragments. Sometimes this peat is 

 found without any mixture of sand ; at other times, 

 where streams have run into the bog or lake while 

 the peat was forming, it is mixed with fine sand 

 that had been held in solution by the water. This 

 last is the best sort of peat for the Erica family ; 

 and therefore, where peat is not sandy naturally, fine 

 white sand, or sand of any colour, provided it be free 

 from irony impregnations, should be procured and 

 mixed with it. This sand admits the water to pene- 

 trate into the soil and reach the roots of the plants, 

 and also to drain away from the roots so as not to rot 

 them. Pots filled with pure peat earth are apt to be 

 either hard, dry, and impenetrable to water, or other- 

 wise as wet as a saturated sponge. 



The climate for the heaths is not required to be 

 warm during winter; if the frost is excluded, that 

 will be enough. Some species, as the E. persoluta 

 for example, will even bear to have the ground about 

 their roots frozen without injury, provided it be not 

 thawed in the sun, or too suddenly, or in a very warm 

 temperature. In general the heaths may be kept in 

 the coldest part of the green-house, and those not in 

 flower in pits, well covered at night with mats, or 

 prepared coverings of reeds or straw. 



Heaths require a great deal of air and light, and 



