A greenhouse allows you to garden earlier in the year and well into winter. In fact, there's something you can be getting on with all the year round once you have a greenhouse in place.
Most greenhouses have to be both practical and aesthetically pleasing. That's because they are usually a focal point in a garden’s design. And so they should be – a wooden greenhouse bursting with sun ripened tomatoes is a joy to behold.

The practicality of a good greenhouse comes down to its usable space. You want as much glass or polycarbonate as possible – then your plants can grow healthily. You also need as big a greenhouse as your space or wallet can afford. Ask any greenhouse owner and all will say that they wished that they'd gone for the next size up. Even in winter when growing is at its lowest point, you will have overwintering plants, potted up onion sets ready for the great outdoors, and seed packets dotted around ready for spring all jostling for space. In summer, well, there will be no room to move in there.

A bigger greenhouse also reduces the massive temperature and humidity fluctuations you get with smaller structures. It can take minutes for the temperature in a tiddler of a greenhouse to zoom to dangerous levels. Likewise, plummeting temperatures affect a small one more. But not many people can have a greenhouse the size of Kew Gardens – so think carefully.

Traditionally shaped greenhouses are still the most popular and are mainly available in wood and aluminium. It depends on your garden design as to which one looks best – wood does tend to be a little pricier but many prefer the look (and smell) of a wooden greenhouse. Any newness in the wood fades gracefully to blend in, contributing a natural feel. Aluminium greenhouses are usually powder coated to ensure longevity and do allow a blast of instant colour. Aluminium doesn't have to aluminium coloured.

Lean-to's are great as they utilise an outside wall of the house. And as they are leaning (or bolted) to the house, they are close by for that five-minute watering session your tasty toms will need every summer’s day. It also makes it easier to run electricity to the greenhouse for all manner of gardening essentials such as electric propagators, lighting, heating and even automatic shading blinds. All of course possible with a greenhouse at the end of the garden, but cheaper to sort.

Whatever you choose, make your interior adaptable to the time of year. In spring, you will need plenty of surface space for trays upon trays of seedlings; whereas, in summer floor space is at a premium as cucumbers, aubergines and tomatoes all mop up the space. And do fit as much automatic equipment as possible. Thermostatically controlled electric heaters are fantastic whereas old style paraffin heaters are good but you do need to light and extinguish them. Vent openers keep the temperature down and if you are out all day, an automatic version will do the job for you.

Think about what you want to grow in your greenhouse and plan accordingly. Just remember – it will never be big enough!