When walking through your local gardening center you’ll be surprised to see just how many different sized and shaped options you have when it comes to greenhouse design.
Depending on your needs, how much you’re willing to spend and the space that you have in your garden, you have options ranging from the basic and most popular standard sized aluminium greenhouse right through to behemoth structures which wouldn’t be out of place as a garden-based conservatory.
Whatever type of greenhouse design you eventually plump for, they all more or less work the same way but the purchase price varies greatly, as do future costs, their usability and how much maintenance they will require as time rolls on.
The Shape Of Your Greenhouse Design
You may think the shape of a greenhouse is important only for aesthetic reasons, but that’s not quite the case. The shape has a bearing on the usability of the greenhouse and how effectively it collect sunlight.

Span Greenhouses
One of the most common types is known as the span greenhouse. This is the familiar rectangle shape with a pitched roof. There is good reason for the popularity of this shape as it provides sufficient growing space along the sides of the greenhouse and, because of the pitched roof, provides plenty of space for even a tall person to stand upright and work. The pitched roof also allows the maximum amount of sunlight to stream into the greenhouse to benefit the plants inside.

Lean-To Greenhouses
If you have a small garden then a span greenhouse may not be the most practical option. In that case, you could opt for a lean-to greenhouse that sits up against the wall of another building such as your house. Lean-tos’ are very practical and have a good balance of growing space to work space. However, they do tend to be slightly more expensive and are more complicated to install due them having to be flush against the side wall.

Dutch Light Greenhouses
A Dutch Light greenhouse is similar to a span greenhouse. However, the difference comes in the way of the slightly sloping side walls which are designed as such to allow more sunlight to enter the base of the greenhouse. Dutch Lights are great for low-growing plants but can hinder taller plants such as tomatoes. The panels are usually larger too which means there’s an extra cost on buying and replacing if you go with glass.

Dome Shaped Greenhouses
Rising in popularity once more, the Dome Shaped greenhouse is designed in such a way that a couple of panes are more or less at right angles to the sun throughout the whole of the day which is the best angle to collect sunlight. Some of the most attractive greenhouses are dome shaped but, they are also some of the most expensive. They aren’t as practical as other shaped greenhouses for tall growth but are just as effective for the smaller growing plants.

Curved Roof Greenhouses
A Curved Roof greenhouse doesn’t strictly have curved glass – though some more expensive models do – but have panes slightly angled compared to their counterparts which when taken together produce a slight curve. The curve allows a little more sunlight into the greenhouse and is more attractive than a standard span, however, this usually comes with a higher purchase price and replacement costs.

Polygonal Greenhouses
If you have limited space in your garden and don’t fancy a lean-to, then a polygonal greenhouse is a good option. In addition, they can be the most aesthetically pleasing to look at than other styles of greenhouse, however, this comes with a price of less functional space. The most simple polygonal is usual the octagon, but with extra cost and the space in your garden, you can have more exotic and sprawling designs.
What Size Should Your Greenhouse Be?
When it comes to what size of greenhouse you should plump for, is it a case that bigger is better? Before we answer that it’s far more important that your workspace is both practical and enjoyable to use and that your greenhouse design is attractive and blends well with your garden.
Size does matter, however. You’ll probably find that once you get working in your greenhouse that you’ll wish you’d gone for that bigger design that you eyed, so perhaps you should go for the bigger greenhouse that you first think you’ll need!
Think about where you’ll be siting your greenhouse and measure out the space you have available. You’ll need access to each side of your greenhouse and so reduce the space you measured initially by about 1.5m on each side, maybe more if you think you’ll be working around the sides or be moving tools and equipment near to where you will site your greenhouse.
You also need to consider what height you’ll need. If you plan working within your greenhouse for some time, then you’ll need to be comfortable standing at benches and shelves. Your own height will help you determine how high your greenhouse should be. With a height of 5ft at the eaves, you should have about 7ft at the peak of the roof which should be sufficient for most people. Also, the higher your roof, the more sunlight is captured by the greenhouse and the taller the plant you’ll be able to grow.
Materials Used In A Greenhouse Frame
When it comes to the structural frame of your greenhouse, you are faced with the choice between three primary materials.
Aluminium is the most common material used in the construction of greenhouses. It’s quite a strong metal which means that the structure itself need not be too hefty which results in lest shadow being cast onto the plants inside. Additionally, there is very little maintenance needed for its upkeep over the course of the greenhouses’ lifetime. However, aluminium is also flexible and this is its one disadvantage when forming the frame of a greenhouse. Cheap greenhouses can suffer warping and bending of the aluminium which will mean they will need to be replaced. When looking at aluminium greenhouses, make sure there are plenty of cross braces and that the frame itself is sturdy.
Wood is much more pleasing to the eye when used as the material for your greenhouse in addition to the greater sturdiness of frame it provides, certainly much better than aluminium. It also happens to provide the best base when installing accessories within the greenhouse such as shelving and plant supports.
Unfortunately, wood is susceptible to the conditions within your greenhouse and doesn’t take too kindly to the damp and humidity. As such, you’ll need to perform regular maintenance on your wooden greenhouse and stamp on rot as soon as you discover it. You could ensure that your greenhouse is fitted with guttering to help with the issue but regular inspections of your frame will be necessary.
UPVC is becoming more popular as material to use in the frame of greenhouses as the use of double glazing is becoming more common. There is next to no maintenance upkeep with UPVC but you will find that you have to pay for the privilege as this material is the most expensive of each of those listed here.
Greenhouse Glazing
Glass is the most common material used for greenhouses but it’s not the only choice. Each of the glazing options below have their advantages and disadvantages and you should think carefully before deciding upon your option.
Horticultural glass is thinner than the glass you’ll find in your home and allows sunlight through and into your greenhouse more easily. Damage aside, glass will last for the full lifetime of your greenhouse and is easy to install. You can also double glaze your greenhouse for an extra cost at start up but the downside of this is that sunlight doesn’t travel as well through double glazing as it does a single pane.
Twin Wall Poly-carbonate is an inexpensive for of glazing for greenhouses. There are two layers of plastic sheeting with air trapped between them which aids in the insulation of the greenhouse, however, the downside of this is that less sunlight manages to get through to your plants and this is a problem that will increase with age and so will need replacing regularly.