Buying the right greenhouse

Planning to grow your own plants and vegetables this year? Create a protected growing environment for your seedlings with a our handy guide of considerations when buying a greenhouse

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greenhouse can be one of the most valuable additions to a garden and offers the opportunity to grow a much wider range of plants, often making these available earlier or later in the year. Despite the array of designs available, the simplest constructions are usually adequate for many gardens. A greenhouse measuring 2.5 x 5m (8 x 16ft) will provide sufficient space for most needs.

Materials

Aluminium is usually the best material for a frame, as it needs little or no upkeep and casts little shade. Wood, whilst attractive, needs periodic upkeep and the bulkier frames can cast excessive shade inside the greenhouse.

Glazing

The best glazing material is glass, as it allows the passage of 90 per cent of external light through, and does not degrade in sunlight. It also helps to reflect heat radiated from within the glasshouse back into the structure. Polycarbonate sheeting is resistant to breakage, lightweight, durable in adverse weather, and good at retaining heat, yet only transmits 83 per cent of the external light.

Growing conditions

To maximise the success of greenhouse growing, the conditions within it should not fluctuate widely, so do invest in a maximum/minimum thermometer to help you to control the temperature inside. Ensure the design you choose has provision for ventilation to avoid it overheating in summer months, and can be insulated easily for winter. Roof vents are the most useful, and ideally should be on both sides of the roof ridge and equivalent to 15-20 per cent of the floor area.You can even get thermostatically controlled vents that open as the temperature inside rises.

It is wise to provide some shading, too, such as a white shading paint applied to the inside surface of the glass that reflects some of the light. Shade netting can prove effective, although this allows all of the light through the glass and tends to absorb the heat from it. It can also reduce the quality of the light that does reach the crop.

Layout

Carefully plan the layout of growing areas inside to use every available bit of space. Many greenhouse plants will grow well in open soil borders, in ground prepared in a similar way to borders outside. Grow bags are an alternative if the greenhouse has to be placed on a hard standing or paved area. A shelving system might be better if you want to grow specimens in pots, and has the advantage of enabling you to work at a comfortable height. It is particularly useful for raising seedlings and propagating plants.

Alitex-National-Trust-Hidcote

The National Trust range from Alitex is an ideal choice for a period garden. There are seven low-maintenance aluminium designs; the smallest, the Hidcote, is perfect for fruit and vegetable growers. There’s room for one bench with beds on either side. H290xW300xD260cm, priced from £10,250 with brick base

The elegant proportions of the Hartley Botanic Grand Lodge greenhouse enhance light flow and plant growth.

Gabriel-Ash-Grow_and_Store

Need a greenhouse and a shed? The Grow and Store greenhouse-shed combi from Gabriel Ash serves a dual function. The innovative design is ideal for small gardens and has an internal door to keep in the heat or let it out. H270xW270xD240cm, from £4,950

Birdlip-mill-46

Big on features and performance, this Eden Birdlip greenhouse is one of the smallest in the range. Made in aluminium, it has a Zero Threshold door system for jam-free operation. H210xW150xD190cm, it costs £429

after

If you need a glasshouse designed to fit into existing architecture, consider the bespoke service from Dovetail Greenhouses. This Dovetail Bespoke model is crafted from powder-coated aluminium, H280xW370xD320cm, priced £9,750

decagon

Fawt’s attractive Decagon greenhouse creates an ideal centrepiece in a small garden. Suitable for siting on earth, gravel, concrete or paving stones, it costs £2,161 delivered but not installed, for a green, white or brown finish, H240xW240xD240cm

Deco-1

A traditional White Cottage greenhouse combines the benefits of a powder-coated aluminum roof with the authenticity of timber. There are three standard Edwardian glasshouse styles including this pretty Deco model, H230xW190xD200cm, £4,349