2 
INTRODUCTION. 
the same time, great care must be taken not to suffer any stagnant water to remain about the 
roots; as, if that were the case, they would soon decay. 
A greenhouse requires still more care than a conservatory, as the plants are aU in pots, and 
these pots are generally small. Plants in pots are in a most unnatural state, as their roots are 
not only confined to a very small space, but they are exposed to much greater alternations of 
heat and cold, moisture and dryness, than plants can be in the free sod. On this account, plants 
in a greenhouse require to be watered oftener than those in a conservatory. In the winter, 
plants in a growing state in a greenhouse should he watered twice a week, whereas in a eonser- 
vatory once a week wiU be quite enough ; and in the summer they should be watered every day, 
and in veiy hot weather twice a day; though in a conservatory every other morning will he 
generally found sufficient. It must be observed, however, that regular watering should only be 
given to plants in a growing state. A season of repose is as necessary to plants as sleep is to 
animals; but the rest of plants lasts longer, and is taken at intervals wider apart. When plants 
are in their native countries, they cease growing at certain times from the changes in the seasons, 
and other natural causes ; hut when plants are kept in a greenhouse, their season of rest must 
depend upon the gardener, who gives them repose by withholding water almost entirely. The best 
season for giving plants repose is just after they have ripened their seed, if they are permitted 
to bear seed ; or just after they have flowered, and the flowers have fallen, if they do not produce 
seed. The necessity of giving plants repose was not understood formerly ; and tliis is one principal 
reason why greenhouse plants, particularly geraniums, are so much finer now than they used to be. 
Greenhouse plants are now also planted out much more commonly in the open air than they 
used to he, and for this purpose euttings are made in autumn, and struck by plunging them 
into a hotbed; and the plants thus raised are kept during the winter in what is called a cold 
pit, and they are planted out in May or June. A cold pit is formed by making an excavation 
in the ground about two feet deep, and lining it with brick. On tliis is set a frame with glass 
lights, like that used for a hotbed, and the plants which are put in it are kept as dry as possible. 
Air is given every mild day betiveen ten and three o^ clock ; and the glass lights are covered with 
mats every evening between foui- and five, when it appears at aU likely to freeze. 
In the present work, when the plants I describe require any particular kind of culture, I shall 
mention it under the head of “ Description, &c. ; ” but when I say nothing of their culture, it 
must be understood that they require no other care than the general routine cultm’e which I 
have above described. In the general arrangement of the work I shall follow the same plan as 
I have adopted in the previous volumes of this series. 
