There is a huge variety of greenhouses on the market and the right choice depends a great deal on budget and size.
But when it comes to the materials, with a few exceptions the choice tends to come down to wood or aluminium for the frame and glass or plastic for the windows. So what are the pros and cons of each and which one’s the right choice for you?
Let’s take aluminium first. It’s light, durable, impervious to damp and usually cheaper than wood. But it’s not as sturdy and the individual sections of frames can be bent very easily. This flexibility is great when you are putting an aluminium framed greenhouse together, and the whole building takes on more rigidity when assembled.
But an aluminium frame will not be as strong as a wooden frame and the assembly as a whole is lighter. This makes them less able to withstand very high winds. The other disadvantage is that if the spars are bent or broken by high winds, they aren’t easy to repair, they can only be replaced. And that’s if the manufacturer will sell spare parts.
Wood, on the other hand, can be repaired by replacing sections of frames or by rubbing down, filling and re-coating. Having said that, wood will show the ravages of time and weather more easily and requires rubbing down and retreating anyway, even if there’s nothing wrong with it.
This can be done annually although in most parts of the UK you can get away with leaving it for up to five years between sessions, as long as the wood is properly treated before the greenhouse is assembled. Finally, although wooden-framed greenhouses are more expensive than their aluminium-framed counterparts, most people agree that wood looks a lot better.
When it comes to glazing, glass and plastic are available for both wooden-framed and aluminium-framed greenhouses. The pros and cons are a lot simpler here, plastic is lighter and cheaper but relatively short lived, glass is superior in almost every way but more expensive.
Of course, plastic panes won’t crack and snap like glass does, so plastic could definitely be a consideration if you have children running around the garden. It’s safer for them too.
Best Glazing for Plants
When it comes to properties to help nurture growing plants, it’s not such a clear-cut case. Glass is colder to the touch than plastic and that gives a clue to the fact that it will let heat out more readily than plastic. But glass is also more efficient than most plastics at transferring light through to the growing areas.
And even the plastics that are more efficient than glass will not remain so for very long because plastic scratches easily and goes opaque with age. Glass is harder to scratch and can be cleaned without affecting light transmission properties as long as the right cleaning materials are used.
To be honest, we wouldn’t be surprised if you have arrived at the end of this article and are still confused about the best choice. It’s a complicated subject and there are a lot of contradictory pros and cons for both frames and glazing for greenhouses.
But work through it step by step, then take a wander round a garden centre or DIY store to look at a few options, and you’ll soon know what’s right for you.