Greenhouse Gardening Tips for the Beginner Gardener
Greenhouse Gardening Tips for Gardening under Glass
A greenhouse opens new gardening horizons, and most keen gardeners must at some time think of the very considerable advantages ownership bestows. With a heated greenhouse, gardening becomes a year-long hobby rather than one concentrated on the warmer months. But even without heat, or with just a modest amount during spring, the extra interest provided is remarkable.
If cost or space precludes the possibility of a greenhouse, many of the benefits to the plants are shared by cold-frames and cloches. These are of particular use in the vegetable garden, but they can also greatly increase the range of flowers that can be raised or grown successfully.
Greenhouses and Greenhouse Gardening Tips
A greenhouse greatly enlarges the scope of your gardening, saves the costs of buying many kinds of plants, and provides plants for the living-room, as well as enabling you to propagate particular subjects which are costly or in scarce supply, or may not be generally available in plant form. A greenhouse also allows you to work comfortably when outdoor conditions are wintry.
Types of Greenhouses
There are many types of greenhouses and because they can vary greatly in size and shape, this is the main question to be resolved before you purchase one.
Size of the Greenhouse
is mainly a matter of space, price and growing requirements, and this tends to resolve itself. But remember that the proportion of growing space lost to the central path is much greater in a small greenhouse than in a larger one. In many instances the smaller type also have low eaves and doorway clearance, so bear this in mind if you are tall. You want to spend many pleasant hours in the greenhouse, and this will be impossible if there is insufficient head clearance for comfort.
Shape of the Greenhouse
Shape can be a more difficult question. In days gone by there were just a few conventional shapes from which to choose, but modern materials and designs have changed all that.
Most gardeners, however, will choose one of the conventional types, and the choice usually lies between a ridge or span greenhouse (which is free-standing with a sloping roof and either straight or sloping sides) or a lean-to (which uses the wall of a house or shed on one side). There is a compromise between the two that is sometimes seen a three-quarter span, which has two roof surfaces to catch the sun yet also utilizes an existing wall.
Fairly recently there has been a movement away from these orthodox shapes and there is even an octagonal greenhouse, which is effective because it catches most of the available light.
Whatever kind you consider buying, compare it with the available growing space of other types. Also look at the efficiency of the ventilation system. These points can be more important than shape.
What are Greenhouses Made From?
During recent years some prominence has been given to the use of various forms of plastic or polythene as an alternative to glass, but glass is still the best proposition for a greenhouse. It is easier to clean, does not scratch, and will not accumulate as much dirt, which reduces the quality of light transmitted. And, of course, it normally has a long life.
Plastic greenhouses are, however, suitable for providingfor various plants, and a polythene lining is of value for the cold or cool greenhouse, preventing the temperature from falling very low at night.
Another important decision is whether the structure should be of wood, metal or concrete. Teak is expensive; Western red cedar durable and cheaper. Painting is unnecessary, but it should then be dressed with linseed oil occasionally. Oak is much in demand, and when used with a steel framework the cost is less.
Metal greenhouses – steel and aluminium alloys – are easy and quick to erect and admit plenty of light because of the smaller framework. However, the larger area of glass can mean greater fluctuation in temperature, and draughts are unavoidable when putty is not used.
Concrete greenhouses are mostly constructed of precast strips, the glass panes being secured to the strips with asbestos from beneath. They do not look as elegant as the other types.
Siting the Greenhouse
The siting or placing of a greenhouse is important. The aim should be to provide full sun exposure not in the shadow of trees, fences or buildings from the east, south or west. On the other hand, avoid positions exposed to strong winds, especially from the north and east.
The traditional alignment is north and south, although some growers prefer east and west because of the improved transmission of light during winter.
Another situation to avoid is one where children are likely to kick balls or throw ‘stones, which would be particularly risky in the case of glass-to-ground structures.
Every permanently placed greenhouse must have a proper foundation, and many manufacturers supply a ground plan.
A simple foundation can be made by taking out a trench of the right depth, keeping the sides vertical. Sometimes a wedge of concrete at least 30cm (12in) wide and 13cm (5in) deep is made, and a brickwork footing built on it. If the house has a brickwork base, several courses of bricks should be used. Concrete bricks, including the cavity type, can be employed for footings and walls.
Good surrounds and a proper soak-away for water are other considerations, while a hard approach path should be considered essential.
Erecting a Greenhouse
Before erecting a greenhouse, check with your local authority or landlord whether permission is required. There may be regulations if it is to be sited close to the house.
Timber greenhouses usually have prefabricated wall and roof sections, like sheds. Many are supplied with precast concrete base plinths, which are simply placed on levelledand to which the walls are anchored. If these are not used, the greenhouse must be set on a single course of bricks on a concrete strip foundation.
Most aluminium greenhouses are supplied in packs of separate components which bolt together according to the manufacturer’s instructions. The walls can be erected on an aluminium strip or precast concrete base laid on level ground.
The glass is usually bedded on a flexible glazing strip and is held securely in the aluminium sections using stainless-steel clips.
Greenhouse gardening tips for the beginner greenhouse gardener or even the pre-beginner greenhouse gardener, would perhaps be to initially try growing plants in garden frames or cloches.
Although garden frames should really be considered as an annexe to the greenhouse, giving winter protection to plants that will stand a degree or two of frost; accommodating flowering plants out of bloom, or subjects for which the greenhouse would be too warm, except in winter. They are invaluable for early sowings, raising bedding plants and for hardening-off plants raised in early spring. The value of a frame is vastly improved if it can be heated. This can be done inexpensively by making a hot-bed or by using soil-warming cables. A very small paraffin stove can also be effective, especially if the frame is situated in a sheltered south-facing position, unshaded by either trees or buildings.
The original garden cloches were bell-shaped but now they are chiefly of a tent or barn-like or tunnel form and can be set together to form long rows for plants. Flat-topped cloches are also available, while several of patent design provide for easy access, watering and ventilation. Various types of plastic are used as glass substitutes, but these are not so easy to fix in a stationary position because they are light.
Garden cloches begin their usefulness early in the year, for they can be positioned to warm the soil for seed-sowing or planting tenderraised in the greenhouse. They are invaluable, too, for raising bedding plants, pot plants and as cover to harden off plants raised in warmth. They can be used to cover and bring into early flower hardy subjects such as anemones, (Hellebores niger), pansies ( x wittrockiana), polyanthus ( polyantha) and spring-flowering bulbs. They are also most valuable for covering early vegetables, such as early beans, , lettuces, and . And for sheltering tomatoes.