GREENHOUSE. 
Fig. 33.—Greenhcuse and Vinery inside. 
glass. It is not usual in green- 
houses of this shape to have any 
path behind the pots; but, in this, 
a concealed path is left at 6, which 
may be masked by Thumbérgia 
alata, or some other climbing-plant, 
so as to enable the gardener to get 
on the path d, to water the plants 
on the shelf (a). The stage may 
be composed of flagstones supported 
by brick piers (c). ‘There is a front 
shelf for bushy ornamental plants at 
e. This house is to be heated by 
hot-water pipes, shown at f; or by 
smoke-flues in the same _ space, 
omitting the pipes. A house of a 
different description, in which vines 
may be grown, and manure intro- 
duced to afford bottom-heat, is shown 
in figs. 32 and 33. This house is 
only intended to force flowers, so as 
to have Roses at Christmas, &c.; 
or to keep them during winter; and 
237 
GREENHOUSE PLANTS. 
it has no heat but what is afforded 
by the manure. Where horses are 
kept, this house is a very cheap one. 
GREENHOUSE Puants are those 
which will not bear the cold of a 
British winter in the open air, but 
that only require to be protected 
from frost. Many persons injure 
their greenhouse plants by giving 
them too much heat in winter, and 
too litle air in summer, and are then 
| Surprised to find their plants die, or 
at least become sickly, and remain 
without flowering, notwithstanding 
all the care that has been bestowed 
upon them. No greenhouse ought 
to be kept at a greater heat at night 
| than from 35° to 40° during winter; 
but the thermometer ought never te 
be suffered to fall below 35°. In 
the day, particularly if there be 
sunshine, it will of course rise high- 
ler; but the fire should be lessened 
accordingly, as the thermometer, 
even in sunshine, should not rise in 
winter above 50°, or at most 52° or 
53°. A higher temperature will 
|induce premature vegetation; and 
the plant will waste its strength in 
an abortive attempt to produce 
flowers and seeds at a season when 
its nature requires it to be kept in a 
state of complete repose. The 
second fault, of giving too little air, 
is an equally serious one. Plants 
can no more live without fresh air 
than without water; and even in 
winter, the sashes of a greenhouse 
should be opened for an hour or two, 
say from twelve till two, in the mid- 
dle of the day, whenever the sun 
shines, or the frost is not too intense. 
In the summer, say from the middle 
of May to the middle of September, 
the plants should be set out in the 
open air; the space on which they 
are to stand being covered two or 
three inches deep with small coal or 
slack, or ashes, to prevent the worms 
from creeping out of the ground 
into the holes at the bottom of the 
pots. In cold and damp seasons, 
At 
