IN THE GREENHOUSE
Only the owner of a small heated greenhouse knows the joys of greenhouse gardening in the dull days of winter. As early as December the first spring bulbs give a bright and welcome contrast from the cold and dismal weather outside.
Although there are now many newer types of greenhouse on the market the one of wooden construction has not been ousted. It requires painting every two or three years, but wood has the definite advantage over other materials in that it is a slow conductor of heat. This means that it absorbs the heat of the sun slowly – and is capable of holding it for a long time.
It is important to give the house a thorough cleaning every year. Choose a time between crops and wash over all the glass and woodwork with soft soap and water to which is added a little disinfectant such as carbolic or lysol. This makes certain of getting rid of any pests. The brickwork of the walls should be whitewashed, and the paths, if they are also of brick, thoroughly swilled down.
Watering is as important a part of greenhouse gardening as ventilation and shading. Some plants like a moist atmosphere as well as water at their roots, whilst others prefer to be kept on the dry side, As a general fule very little water should be given in the winter, and more should be added as the growing season advances until the resting period is again reached. Water should not be given in driblets, but a plentiful supply applied when necessary, filling the pot to the rim. Rapping the pots with a rammer or the knuckles shows whether or not water is required: a high-pitched tone ,denotes dryness.
Do not give water when it is not needed as this makes the soil waterlogged. On hot days spray the paths and walls of the greenhouse with water. Not all plants like water on their leaves, and care should be taken not to cause mildew and damping off by this method.
A lean-to greenhouse enables the gardener to take full advantage of a bare wall. A southern ‘aspect allows for a wide choice of plants, but any aspect other than due north can be satisfactorily employed.
A three-quarter span is a more elaborate method of constructing a greenhouse against a wall. It affords light and ventilation on both sides, the ridge being slightly higher than the top of the wall.
In the three-quarter-span type of house staging can be had on both sides of the path. Against the wall it should be raised on two levels to enable the plants to gain the maximum light. In a lean-to house a border for a vine, peach or ornamental climber is left against the wall.
Top ventilation is the most essential of all types. Wherever possible the ventilators should be on both sides so that opening can be adjusted according to the wind. Always ventilate with a rising
temperature and never allow the thermometer to stand too high before air is given, thus causing a sudden drop. Side ventilation is only used in summer weather when it cannot cause a draught. Always close the house early, particularly in the duller months, so as to shut some of the sunshine into the house to maintain a genial atmosphere during the night. This applies to both types of ventilators.
Having decided upon the type of heating apparatus and ventilators the interior plan of the greenhouse should be considered. Shelves should be arranged so that water does not drip on to plants below. The path should be no more than the width of the door, usually 2 ft. 6 in. Staging of slatted wood to allow free circulation of air around the plants is most often used. Solid stagings of sheet zinc, or other metals which do not rust, supported on solid wooden framework, are often used in conservatories. These must be covered with coarse sand, washed pebbles, or clean small clinkers. This has the advantage of conserving moisture and during the annual cleaning can be washed, in a sieve. When adopting this method the edge of the staging can be clothed with tradescantia or helxine rooted in a narrow ribbon of soil.
During the early spring the house is always very, crowded with annuals and vegetables for first crops being raised. An extra temporary shelf makes room for many more boxes. Wooden planks about 1ft. wide slipped into metal supports fixed to the roof are easily moved.
When installing heating pipes in a greenhouse do not try to economize by reducing the length of piping to be fitted. The most satisfactory results are obtained from large areas of low temperature pipes. Very hot pipes tend to dry the atmosphere too much, and encourage attacks of red spider. Stoking is easier with plenty of piping, as a large quantity of water will retain its heat all night in cold weather; an extra stoking late in the evening is essential when the house has insufficient piping. As well as the extra labour involved the fuel bill will be higher. Avoid the temptation of throwing rubbish under the staging. The ground round the pipes must be kept
OIL AND GAS HEATING
1. For the small greenhouse a paraffin oil heater can be placed to keep the atmosphere humid.
Is very convenient. The blue-flame lamps will 2. By gas heating a winter night temperature burn for forty-eight hours without attention. Of 45 degrees Fahr. Can be maintained. The Most are fitted with a trough In which water inside boiler surface supplements pipe heat.
THE SERVICE CORNER
The key to the successful and economic garden is the service corner. Here the tender plants can be protected during the winter, and half-hardy annuals and vegetables raised from seed prior to planting out in their permanent quarters. For ease in working the potting-shed with its supply of soils, the green-house and frames should all be in close proximity.
FOR SUN AND AIR
1. Where possible set the greenhouse running north and south and the frames facing south to obtain the maximum amount of sunshine. Ventilating should be away from the wind.
2. A span frame gives more scope than the ordinar9 one or two-light frame because it allows for taller plants, and it also gives opportunity for ventilating more freely even jn windy weather.
FRAMES FOR PROPAGATING
Frames used for propagating will house pots and boxes of seedlings and cuttings until they are ready to be stood outside. Successive batches can be handled throughout the spring and early autumn, thus using the frame to Its fullest capacity. During the summer, indoor plants and bulbs can occupy the space while ripening off, and frame will also be useful for forcing tulips, narcissi, lilies of the valley, etc. Alternatively, a bed of good soil can be made up In the frame to grow early lettuces, carrots, brussels sprouts, cauliflowers and radishes.
These are the basics of greenhouse gardening. Check the rest of the site for more specific information how to grow plants in a greenhouse.