68 Ferns and Fern Culture, 
freezing point. When frost penetrates, it immediately 
affects everything damp. It often breaks pots, and 
when it is severe it hurts the roots against the sides.. By 
covering the place with mats or other materials, the 
effects of the frost may be reduced considerably, and hy 
plunging all pots in cocoa-nut fibre or leaf mould the 
evils may be further reduced, resulting in undoubted 
benefit to the plants, 
VENTILATION. 
Means for ventilation should always ‘be provided. 
Ferns must not be subjected to cold draughts, yet ‘a 
gentle imperceptible supply of fresh air given at the pro- 
per time will prove of great benefit. There must be pro- 
vision for the entrance of this at the lower part of-the 
house, and for the escape of hot air at the top. 
Often there are no means provided at the bottom for 
the entrance of air, and when the ventilators at the top 
are opened, a cold current at once rushes in, causing the 
moisture to condense upon the foliage. In winter this 
is particularly injurious to the plants, chilling them and 
leading to discolouration of the foliage. By opening 
ventilators at the bottom the fresh air enters at the pro- 
per place, while the hot air freely escapes at the top. An 
upward current is thus produced which prevents chilly 
down draughts. a : 
Ventilation may be given whenever the temperature 
is high enough, care being exercised not to open. the 
ventilators so wide that the temperature is suddenly 
reduced. On windy or cold days special care will be 
necessary. Air should be given as early in the morning 
as possible, and left on as long in the afternoon as is safe. 
This conduces to a sturdy growth, the foliage being 
harder and more enduring than would otherwise be the 
case. 
WATERING. 
There is more importance attaching to the watering of 
plants than many people imagine. It must not be done 
in a haphazard or careless manner, for injurious watering 
causes a long train of evils. A clear and perfect know- 
