I don’t have a greenhouse, but would really love to own one. As a boy I had a tiny 6’ x 4’ glass to ground, wooden frame greenhouse that I really loved. It was heated with a paraffin heater, lined with polythene sheeting to insulate and far too small for what I tried to cram into it.
My benches were made from sheets of corrugated iron and bricks and plants, seed trays, and a host of other containers grew everything from orchids to shrimp plants.
My greenhouse was my little world: damp, usually cold, uncomfortable but totally magical and my first port of call every day when I got back from school. Ideally I would have slept there!
Now I have a two acre garden, loads of room, but have I got the right place for a greenhouse, and if so, what sort of greenhouse would I buy? To help me decide, and to help you, I thought I would outline what we should consider when buying a greenhouse.
Your greenhouse needs to be in an open position where it will get plenty of light. However it needs to be sheltered from strong winds which could cause damage as well as have a cooling effect.
A greenhouse needs to be close enough to the house, both for access and to get power to it easily. You will get more from a greenhouse if you heat it and electricity is the obvious option. Site it miles from the house and you will spend a lot of money putting in a power supply.
You also need to think about water supply. You might manage with a water butt – will the hose reach it when you need to top up in summer?
A greenhouse needs a level site with some space around it to allow access for maintenance and cleaning. Also standing space for plants you want to move outside, either for a summer holiday, or before they move out permanently into the garden.
Which is best: glass or plastic?
Greenhouses were traditionally glazed with horticultural glass which is thin and inexpensive. It does break fairly easily if knocked from inside or out and breaks into sharp shards.
The trend is towards safety or toughened glass which is stronger and breaks into more manageable pieces if shattered. It is more expensive, but worth the investment.
Plastic glazing is usually with twin-walled polycarbonate sheets. These give a more translucent light which is beneficial in summer, but not in winter. They tend to discolour with age and can blow out easily. Their appearance is less attractive and a greenhouse is a prominent feature.
Which is best, wood or aluminium?
Aluminium frame greenhouses are usually less expensive and maintenance free. They are available in natural aluminium which weathers to a soft grey, and green or other colours which are more expensive and can need maintenance in time.
From the appearance point of view a classic, beautifully designed hardwood framed greenhouse takes some beating.
Yes, it is more expensive and will need some maintenance, but it will be a feature in the garden, rather than an eyesore. Western red cedar is a good choice, it turns silver with age and is very durable.
Glass to ground, or half glazed?
Glass to ground is better for crops grown on the greenhouse floor such as tomatoes and cucumbers. It gives more growing height and gets light right down to the base of the plants.
Insulation is usually less so it costs more to heat in winter. The lower glass is more susceptible to damage both from inside and out. Take care with passing wheelbarrows.
Half glazed with wall or timber panelled sides is a better choice if the house has benches. These raise plants to waist height - easier to manage. Equipment, pots and anything under the benches is hidden so the overall effect is usually more pleasing. Better insulation means less heating costs.
What’s the best size to buy?
Quite simply the biggest you can afford and accommodate. However big the greenhouse, if you are a gardener you will fill it. A new greenhouse always looks quite big and the possibilities are endless. You will get carried away and you will try to grow more than you can accommodate.
Think about height and what suits you. Some budget greenhouses compromise on height which makes working in them difficult and uncomfortable. Make sure you buy one with sufficient headroom.
There are lots of budget plastic “greenhouses” on the market. The term is misleading. Most of these are vertical cold frames that will protect a few seedlings. They will not satisfy the craving for a greenhouse.
If there is a suitable high wall with space in front of it do think about a good lean-to greenhouse. If it is off the house it will be easy to access, well insulated and give you great growing possibilities.
Alternatively, if you like a project, how about making your own greenhouse with plastic bottles? This has fantastic insulation and it’s all about recycling. I have to say, it’s not bad looking and can be quite a feature – get collecting.
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