Edwards - Greenhouse Gardening: Step-by-Step to Growing Success

Whatever your experience or expertise, a greenhouse offers the chance to extend your gardening activities. You can use it to help save money by raising bedding and vegetables from seed every year, as well as propagating other plants to fill garden beds and borders. If you can install a reliable source of heat, theres an opportunity to get off to an earlier start and grow crops that require a long growing season. In colder climes, a heated greenhouse enables you to grow crops that would not thrive outside, and in a milder climate the options are almost limitless. For many gardeners, though, a greenhouse is a retreat where they can escape the worst of the weather and still carry on with their favourite hobby.

No matter what your reasons are for buying a greenhouse, you will get a lot more from it if you plan carefully and keep a watchful eye on the plants you are growing. This book will help you choose the right greenhouse and enjoy growing success for years to come.

Mini-rose Sunblaze.

Greenhouses are better value today than ever before: a standard 8 6ft (2.5 1.8m) aluminium model is available at low prices everywhere from the garden centre and superstores to the high street supermarket. Having said that, a word of caution. If your choice is governed by price alone you will almost certainly live to regret it. Do not buy in haste.

If this purchase is your first greenhouse then you may well find the specifications from competing manufacturers bewildering. You need to make a checklist of your own requirements and see how each model on offer measures up to it.

Greenhouses are available in a range of shapes (see box). As a first-time buyer of a greenhouse, the shape might not seem all that important apart from the obvious aesthetic consideration. However, the shape you choose should be determined by the type of crops you intend to grow. For instance, if you want to grow bulky crops, such as tomatoes or cucumbers that need to be trained up and along supporting wires, or taller flower crops such as chrysanthemums, then a traditional straight-sided greenhouse with an eave height of at least 5ft (1.5m) would be a good choice. You can still grow such crops in greenhouses with sloping sides, but the growing space will be significantly reduced. High eaves and straight sides will also allow you to put up more staging thereby increasing the available growing space even further. If, on the other hand, you want to extend this rather limited growing season and utilize your greenhouse throughout the year, then a better choice would be a model with sloping sides, because they allow greater light transmission during the critical winter months. Rather smart glass domes are now available and are ideal for the low-growing winter crops like lettuce or displays of prize alpines on staging.

GREENHOUSE SHAPES

TRADITIONAL STRAIGHT SIDES

Widely available

Inexpensive

High eaves ideal for growing tomatoes and other tall crops

Can accommodate large area of bench space

SLOPING SIDES

Fairly widely available

Admits more light than straight-sided model

Cheaper to heat because less volume

CURVED EAVES

Attractive

Admits more light than straight-sided model

POLYGONAL

Attractive

LEAN-TO

Admits more light than straight-sided

Takes less space

Good headroom

The height of the greenhouse ridge should be determined by your height. Surprisingly, ridge heights vary considerably, so if you are over 5ft l0in (1.78m) then make sure the model you buy has a ridge height of at least 7ft (2.1m). You can increase both the eaves and ridge height of a greenhouse by setting the greenhouse on a low wall up to two courses of bricks high. However, this will make access more difficult with a wheelbarrow.

A round aluminium greenhouse.

Size is determined by finances and available space. If you are a beginner taking your first tentative steps into greenhouse gardening then choose a wide, short greenhouse that can be added to as needs and ready cash allow. Check, though, that the model you buy can be added to using extension modules.

A well-managed 6 8ft (1.8 2.5m) greenhouse will offer enough growing space for most gardeners. It is also worth investing in a cold frame, say 3 4ft (90 122cm) to provide additional temporary space in mid- and late spring when the greenhouse is full to overflowing.

If you intend doing some serious greenhouse gardening, then buy the biggest you can afford its even worth doing without some of the accessories for a couple of seasons to get that extra couple of feet of growing space.

Where garden space is the limiting factor, then a lean-to model is worth considering, but do site it against a sunny wall unless you intend growing ferns.

These are designed to be attached to the side of a house or garage. Usually shaped like half a standard greenhouse they take less room and can be more convenient than a free-standing model. The house wall also helps protect it, so lean-tos cost less to heat. If you dont intend heating your greenhouse, a lean-to will provide more frost protection in winter too. Lean-tos can be attached to any wall, provided the mortar is sound and the ridge of the greenhouse will fit under the eaves of the house. If fitted over the back door of the house and will be used as a thoroughfare, its worth putting safety glass in the roof sections. Seal the greenhouse to the house wall using waterproof flashing to prevent leaks that may lead to damp penetrating the house wall.