The Greenhouse. 
151 
former is, of course, the most useful of the two, because they offer greater 
facilities for propagating as well as for growing plants. By their aid, moreover, 
plants may be forced early into flower for conservatory and house decoration, 
a feat which cannot be accomplished by the aid of an unheated structure. 
A heated greenhouse should be provided with sufficient hot-water piping to 
enable the temperature to be maintained at 55 to 65 deg. from October to 
June, if it is required for forcing plants into flower in winter and early spring. 
For ordinary purposes, however, a temperature of 45 to 55 deg. is high enough 
from September to March, and 55 to 65 deg. afterwards. In this temperature 
oranges, myrtles, and oleanders, camellias, and azaleas may be safely grown, 
together with the ordinary run of greenhouse plants. In the higher tem¬ 
peratures Roman hyacinths, lily of the valley, roses, flowering shrubs, azaleas, 
spiraeas, and a host of other plants may be forced into bloom from Christmas 
onwards. Not only this, but vegetables, such as rhubarb, seakale, and French 
beans, may be forced into early growth, and early supplies of saladings 
grown too. Grapes and other fruit do not come within the scope of this 
work; hence they cannot be dealt with here. Wherever there is a con¬ 
servatory a heated greenhouse is a sine qua non for ensuring a supply of 
flowering and other plants for its decoration; for, as everyone will soon 
find to their cost, plants cannot be grown continually in a conservatory. 
Another important point, it should contain a propagating frame for raising 
plants from seeds and cuttings. But granting all this, an unheated green¬ 
house is not to be despised. It is true it cannot be turned to such profitable 
account for ensuring early supplies of flowers and vegetables, but it may, 
nevertheless, be turned to good use and made a source of interest all the 
year. In early spring, for instance, bulbs in pots, together with alpine 
primulas, primroses, and many of the lovely alpine plants that are generally 
grown on rockeries—these can be removed outdoors in May, and their 
place taken by tuberous begonias, zonal pelargoniums, and similar plants. 
When autumn arrives, chrysanthemums galore may worthily supersede these, 
to be followed in November by ornamental foliage and flowering shrubs, 
with a collection of Christmas roses in pots. If preferred, tomatoes or 
cucumbers may take the place of the summer plants; and so, after all, a 
cold greenhouse may really be profitable as well as interesting. Wherever 
possible, it is a wise plan to build the greenhouse sufficiently large to enable 
it to be divided into two compartments—the one heated and the other cool. 
This will enable seedlings, cuttings, and other plants that require their growth 
