In greenhouses where plants requiring very different optimum temperatures and illumination are kept together.
As regards water, its deficiency or excess is a relative matter, and although many of the minor maladies of pot-plants in windows and greenhouses controlled by amateurs depend on its misuse, water alone is probably never a primary cause of disease.
Travellers are especially struck with the beauty of some of the wild flowers, more especially with the lilies and convolvuluses; and European greenhouses have been enriched by several Formosan orchids and other ornamental plants.
The most familiar species is P. senilis, a Mexican plant, which though seldom seen more than a foot or two in height in greenhouses, reaches from 20 ft.
When cultivated in greenhouses liliums are subject to attack from aphides (green fly) in the early stages of growth.
In these circumstances " syringing " and " damping down " are of value in cooling the temperature of the air in hothouses and greenhouses and increasing its humidity, thereby checking excessive transpiration.
Pipes should also be laid having a connexion with all the various greenhouses and forcing-houses, each of which should be provided with a cistern for aerating the daily supplies.
I jects, the smaller size of house already recom mended for greenhouses, a: o 00 namely 20 ft.
In their interior fittings plant stoves require more care than greenhouses, which are much drier, and in which consequently the staging does not so soon decay.
In some places movable greenhouses have been erected for market purposes, so that the soil may be exposed to the sweetening effect of the weather, when the glass roof is moved to an adjoining patch.
The white-fly is now a common pest in greenhouses, the nymphs being greenish scale-like objects on the under sides of the leaves, and adults very small white flies.
It is also applied to the strait between Mallicollo and Espiritu Santo Islands of the New Hebrides group, and the South American climbing plant Bougainvillea, often cultivated in greenhouses, is named after him.
It is well to set the plants under the benches or on the walks of the greenhouses; if they are in the parlour move them away from the cold point and protect them with paper; this will usually save them even if the thermometer falls to 24° or 26 °.
Never have I found in the greenhouses of the North such heart-satisfying roses as the climbing roses of my southern home.