Growing Fruit in the Greenhouse
Before going too deeply into the practical aspects of actuallyin greenhouses, it would be as well to start the story at the beginning by looking at the itself and the various pieces of equipment that may, or may not, be needed.
We have to assume for a start that the greenhouse is not going to be used solely for the production of fruit. In most households this would be wholly uneconomical and would rather restrict one to growing exotics likeand , both of which, incidentally, are perfectly possible in this country. The sort of greenhouse we are talking about here is the ordinary run-of-the-mill type that any gardener would be only too happy to own.
If it is heated, so much the better because this will enable you actually to force fruits, and other plants, into maturity earlier than in an unheated house. However, heating is by no means an essential part of growing fruit; unless, as already mentioned, you are proposing to go in for exotics. But with heat, there comes the ability to raise your own bedding and half-so, although not vital, it’s a big advantage.
Even before that, though, you should sit down and work out just where the greenhouse is going to be sited. Obviously much will depend on the size and shape of, but a number of considerations should be taken into account.
Siting the Greenhouse
It should be in a sunny position and not overhung by trees. Apart from the shade they may cast, there is always the risk of any falling branches landing on the greenhouse.
A windy site should be avoided. Not only does the wind have a terrific cooling effect, but there is also the chance that the greenhouse could be damaged by moving during gales.
If you want to have mains electricity or water in the greenhouse, make sure that it is sited near a source of either or both of these; it will reduce the cost of installing them.
Try not to site it in too prominent a position so that it dominates the garden; greenhouses are seldom decorative enough for this. By the same token, be sure that a particular position does not create awkward little nooks and crannies that you cannot reach with a mower or where you otherwise make work for yourself.
It’s a good idea to keep greenhouses well away from children’s play areas; greenhouses and children are notoriously incompatible, especially where ball games are concerned.
It sounds obvious, but never build a greenhouse on a slope. Nothing ever opens or closes easily and you will always have trouble with the staging being at an angle.
Type of Greenhouse
Having sorted out a suitable site, or given up the whole idea, you will need to consider whether this will call for a free-standing model or a lean-to. Both have their virtues and vices,
Although a free-standing house gives you more room for growing plants, a lean-to, especially if against the house, is usually easier to plumb in or wire from an adjoining room. It will also stay warmer longer, making use of the heat that the house wall absorbs during the day and releases at night. Also, it will be closer at hand, with the result that you will probably pay more attention to it.
The main problem with a lean-to is that you have little choice in where to position it; sunny walls can be few and far between. Added to that, lean-to greenhouses tend to be darker than free-standing models because all the light comes from one direction.
Deciding on the size and shape of the greenhouse can also be tricky, but you should always try to buy the largest that you can afford, bearing in mind that large greenhouses cost more to heat than small ones. This seems an obvious point, but is one that is often forgotten. Most gardeners tend to grow more plants than they can possibly house, so a big greenhouse is clearly of benefit.
The shape of the greenhouse is usually of much less importance, but it is always better to stick to a traditional rectangular one. Most of the different accoutrements that are available for equipping a green- house are geared to rectangular models.
It’s also more expensive to obtain unusually shaped bits of glass when breakage occurs.
Probably the most frequently asked question when it comes to choosing a greenhouse is whether it should be wood or metal. Once again, both have their virtues and vices.
Wood is a comparatively soft material which will easily take screws, nails and anything else that you may want to stick into it; metal is not and will not. Wood is also a warmer material than aluminium, so that wooden greenhouses tend to be warmer in the winter than metal ones, other things being equal. Whether stained or painted, a wooden house always looks more natural and more at home in a garden than a metal one. This may seem a small point, but a garden should be nice to be in and to look at.
The greater weight of a wooden greenhouse makes it more stable in gales.
Clearly, there are problems with a structure made of wood and the biggest is that, every couple of years or so, the wood needs treating with paint or preservative. Even if a metal greenhouse isn’t looked after, it will last longer than a wooden one.
Metal greenhouses have narrower glazing bars and, therefore, admit more light. This isn’t especially important for fruit, but seedlings during the spring can do with all the light they can get.
Aluminium has been mentioned as a suitable metal for greenhouses and, indeed, this is really the only metal worth considering. Steel is heavy to handle, which makes it difficult to get home and harder still to erect. Added to that, with its increased strength, putting in any fixtures and fittings can be a major operation.
As for glazing materials, glass is really the answer. The only places where it might be sensible to go for thick plastic of the Perspex type is where breakages are likely to occur frequently or where, for some reason, its lighter weight is an advantage. Glass is also a lot cheaper.
Nowadays, it might be well worth considering a polythene-glazed house, particularly if fruit is going to be the main occupant. Polythene certainly does not retain as much heat as glass, but this could be an advantage with hardy fruits because the greenhouse won’t overheat so easily. Also, polythene has to be replaced every three years or so, though this is a small price to pay compared to the far smaller initial outlay.
Bearing in mind that most of the fruits you are likely to be growing in the greenhouse are hardy or, a more important than heating the structure is keeping it cool. This can be a real problem in a good summer.
It is essential to have efficient and effective ventilators. They should also be present both in the ridge and sides of the greenhouse. Fortunately, this is becoming standard practice with manufacturers and it is certainly a feature that should be insisted upon. Ridge vents will let out the hot air all right, but you need side vents to ensure a free circulation of cooling, fresh air amongst the plants. It is well worth considering louvre vents for the side of the greenhouse as, unlike conventional ventilators, they will not get in the way when opened.
Guttering is hardly something that would spring to mind when buying a greenhouse, but one that has gutters is preferable to one without. To start with, they carry water away from the body of the greenhouse which would otherwise simply splash onto the ground and cause problems. In addition, the water can be collected and fed .into a water butt for use in the greenhouse. Rainwater is always better to use than tap-water, particularly in hard water areas.