78 MANAGEMENT OF THE FORCING-HOUSE, 
time in watering was as follows: In the case of under- 
surface irrigation, the water was dipped out of a tank and 
poured into a funnel, through which it entered the various 
portions of the bed. On the other hand, in surface irriga- 
tion, the water was dipped out and applied by a sprinkling 
can, containing either a rose spray or a spout long enough 
to reach all sections of the bed. Inthe former case, the size 
of the plants did not matter, while in the latter, the more 
mature the crop, the more time it required for watering. 
Again, the sub-irrigated beds did not require watering over 
once or, at the outside, twice a week; while, generally 
speaking, the other beds were watered daily. 
‘‘The idea that a water-tight bed is detrimental to plant 
growth on account of lack of drainage is overcome, we be- 
lieve, in the fact that the pipe or tiles receive the excess of 
water, which, in a bed not water-tight, would leak out at the 
bottom, thus making it serve a double purpose. If the soil 
contains too much moisture, it serves as a reservoir ; if not 
enough, it imparts the amount necessary for good condi- 
tions. In either case, the pipe or tiles act as a safety-valve. 
These openings underneath the soil allow free access of air, 
render plant food digestible, and act as a drain to water- 
soaked soil. In view of these results, we feel safe in saying 
that under-surface watering is a pronounced success.”’ 
VENTILATING AND SHADING. 
The one imperative thing to be borne in mind in ventila- 
ting glass houses is to avoid draughts. This means that 
ventilators should be many and small rather than few and 
large, for thereby the warm air can be discharged from 
houses without much danger of an in-rush of cold air, 
because the ventilator sash need be lifted only very little. 
Houses should be cooled by letting out heated air rather 
than by letting in cold air, although it is impossible to 
wholly exclude the outside air when ventilators are opened. 
In forcing-houses of ordinary size, sufficient ventilation can 
