Ferns and Fern Culture. 67 
should be gradually reduced, until by the end of Noveim- 
ber the lowest point is again reached, at the season when 
the days are short and the light faint. At any time the 
temperature may rise 5° or 10° higher, as the result of 
sun heat, but it is not wise to give more artificial heat 
than is necessary to maintain a temperature indicated 
by these figures. 
WARM GREENHOUSE. 
The temperature in December will be sufficiently high 
at 45° to 50° by night, and 50° to 60° by day. As the days 
increase in length the temperature should gradually rise, 
until by the end of May it is 60° to 65° by night, and 70° 
to 75° by day. In August it should begin to decline, 
until the lowest point is reached in November. 
COOL GREENHOUSE. 
In a cool greenhouse the winter temperature by night 
should be 40°, though 35° might not do any harm ; during 
the day 45° to 50° should be maintained. In spring a 
gradual rise should take place, until artificial heat is 
dispensed with for the summer. The temperature, when 
dependent upon natural heat, may sometimes, even in 
summer, be so low, owing to a continuation of wet, cold 
weather, that a little fire heat becomes advisable for a 
short time. On the other hand, there is occasionally such 
intensely hot weather that it becomes difficult to keep 
the temperature down. This may be done by extra 
shading, and a free use of water sprinkled on the paths, 
walls, and stages, or rockwork. — 
COLD GREENHOUSE. 
The temperature of a house where there are no means 
of supplying artificial heat should be regulated during 
winter by outside covering. Perfectly Hardy Ferns are 
the only suitable kinds to have in a house where the 
frost may penetrate, and even for these it is well to use 
all possible precautions to keep out the frost. Hardy 
Ferns will bear many degrees without apparent injury, 
but it is certainly an advantage to them when kept above 
