53§ THE BOOK OF GARDENING. 



Temperature. — According to their native habitats, Ferns 

 require more or less heat; and although it is usually understood 

 that those coming from the Tropics require stove temperature, 

 it is well to point out here that those which are found 

 growing naturally high up the mountains, where the temperature 

 is much lower than near the sea-level, may be cultivated with 

 most success in a warm, and, sometimes, in a cool greenhouse. 

 A much greater number of Ferns than is generally supposed 

 accommodate themselves readily to a comparatively cool treat- 

 ment, under the influence of which their growth is less rapid, 

 but of greater durability. The minimum night temperature of 

 a cool fernery should be 4odeg., which should be increased from 

 4Sdeg. to 5odeg. during the day. A gradual and gentle rise 

 should take place in the spring, until artificial heat is dispensed 

 with for the summer. When, through fluctuation in the 

 weather, the temperature is too low in the summer, it is well 

 to have a little fire-heat at intervals, and when exceptionally 

 hot weather is maintained, the temperature of the cool fernery 

 must be kept down by means of water being freely sprinkled on 

 the floors, on the walls and rockwork, and even by means 

 of .extra shading, if it is found to be indispensable. 



The temperature of the warm greenhouse fernery will be 

 sufficiently high if kept up at from 4Sdeg. to Sodeg. during the 

 night, and from Sodeg. to 6odeg. in the day, from November 

 to March ; it should gradually rise as the days increase in 

 length, so that by the end of May it is 6odeg. or 65deg. by 

 night, and about 7odeg. during the day. It should be gradually 

 lowered from September, until it reaches its lowest point again 

 in November. When tastefully arranged and planted, nothing 

 can be more interesting and enjoyable than such a fernery, 

 which is most pleasing on account of the medium temperature 

 maintained comfortably all the year round. 



In the stove or tropical fernery the temperature need not be 

 so high as is generally the case, and it is far more satisfactory if 

 it can be kept at a moderate degree all the year round ; for it 

 has been conclusively proved that far from being necessary to 

 the comfort of the Ferns, a greater amount of artificial heat than 

 they really require is highly injurious to them. Tropical Ferns 

 may be said to have a period of active growth extending from 

 March to October, and during that time it is advisable to take 

 all possible advantage of the natural heat, which, even when 

 somewhat strong, is not hurtful, provided it is counterbalanced 

 by a corresponding amount of moisture in the atmosphere of the 

 house. The damage is generally done by the use of artificial 

 heat, which should not be resorted to so long as the night 

 temperature of the house does not fall below 6sdeg. ; the solar 

 heat may, without inconvenience to the plants, raise it to 7Sdeg. 

 or 8odeg. at that time of the year, and be maintained all through 



