Siting and Erecting a Greenhouse

There often seems to be some doubt as to whether a greenhouse should be sited north to south or east to west. In practice I find that this makes little difference. I consider it more important to site the greenhouse so that it fits in with one’s other gardening plans: the plants are then positioned in the greenhouse so that their requirements are most nearly matched. Obviously, those plants requiring the maximum amount of sunshine will be placed on the south side, if this can be managed, and those needing less light on the north side. When the sides of the house run east to west then there will be more equable light conditions – but it is really a case of swings and roundabouts.

What is more important is to have the greenhouse near the house or garage so that water and electricity supplies are easily laid on without too much expense. Or if the greenhouse is sited elsewhere in the garden, to make sure that both these services are near to hand. Laying electricity cable, in particular, is liable to be expensive for a trained electrician must do this job. If heating is by oil, electricity is needed for the burner and the thermostatic control, and with gas heating, too, the thermostat is run by electricity.

Erecting any structure, let alone a greenhouse with lots of glazing, may not be everybody’s idea of fun but as in many other areas nowadays ‘do it yourself is a real money saver. It is possible to get a manufacturer to erect a greenhouse for you of any size or pattern desired, but the ‘made to order’ house is inevitably more expensive than one obtained in standard-sized sections for erecting oneself. Indeed, this is the way most greenhouses are bought nowadays and with the instructions provided by the manufacturer this is nothing like so difficult a task as might be imagined.

The house I am going to use as an example of the processes of erecting consists of the sections of two standard houses bolted together end to end. One is glazed to ground level on one side only and the other, a little shorter, boarded to a height of 2-½ ft. all round. The end section is omitted from the longer house, being replaced by the door section of the shorter one. In this way a double greenhouse with a dividing partition is obtained, and one compartment can be kept at a different temperature to the other if so desired.

First, a good foundation is made with concrete prepared with 4 parts all-in ballast to 1 part cement, this being thoroughly mixed dry and then mixed again with water to the consistency of stiff’ porridge. I do not consider it necessary to cover the whole of the greenhouse floor with concrete. In addition to the base on which the framework of the house will stand, all that is needed is a concrete slab path down the centre of the house with ashes or gravel on either side on which plants can be stood. Gravel or ash under the staging rather than bare soil helps to keep the house clean and in addition to being a good standing place for plants can be used to store such things as dahlia tubers and gladioli corms, even if the house has a soil bed for growing tomatoes.

Lettuces and so on, a solid path which can be washed down is an advantage.

The foundations are shaped by shuttering of 6-in planks spaced 6 in. apart. When the concrete is thoroughly dry, bitumen damp-proof course is rolled out on top of it. One side section and one door section are placed in position and carriage bolts driven through the holes prepared by the makers. For extra stability further bolts are partly sunk in the concrete so that they can project through holes made in the base plates and be secured. In this way the complete structure is bolted down to the foundation.

When the side, end and door sections are in position, the roof sections can be slid into place. These are screwed to the side, end and middle sections.

Glazing can be done with one of the putty-impregnated glazing tapes now available or with plain putty worked evenly down the rebates in the glazing bars. Glazing tape has the merit of being quick and easy but whichever method is used the glass will be firmly secured if the job is done correctly. Glazing sprigs are now driven in to hold the glass down. This is most easily done by holding a piece of flat metal, such as an old chisel, against the sprig and striking the metal with a light hammer. Finally the putty is worked well down into any crevices and the surplus removed. All glazing should be done working backwards from one end of the house to the other, one strip from bottom to ridge being completed at a time.

As I have already remarked, manufacturers provide full instructions on the erection of their greenhouses: these notes merely give an indication of the processes involved.

01. March 2012 by admin
Categories: Featured, Greenhouse Gardening | Tags: , , , , , | Comments Off on Siting and Erecting a Greenhouse

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