Home A Guide to Buying a Greenhouse

A Guide to Buying a Greenhouse

Need help to pick which greenhouse is the best fit for you? Check out our comprehensive buyers guide which can help answer some of the biggest questions you could have about what will make this greenhouse right for you. From picking the size, how you should lay out the base and where you should position it – we can help you to be totally confident you know everything you need to make the best decision.

Product maintenance guide Greenhouse Materials

How do I choose the right greenhouse size?

As a functional building, what size greenhouse you need will mostly depend on what you’re trying to grow. If you’re only growing a few pots of basil, you can make use of a smaller shed like our Sprouthouse but if you’re looking to grow some serious produce, you’d be better off with a real grow house like our Growzilla.

However, for a lot of gardeners, the most common complaint with a greenhouse is that it ends up too small after you’ve expanded into more plants. While it may be easy to say “get the biggest greenhouse you can find,” taking into consideration how big your garden is and ensuring there’s enough free space for maintenance is really important.

If you can manage to add a little bit of extra space, say going from a 1.2M wide greenhouse to a 1.8M wide greenhouse, your future self will thank you when you can fit that one extra shelf of pots in.

Different uses for different sizes

What you plan to grow should certainly be a consideration when choosing a greenhouse.

If you’re looking at a Sprouthouse, you’ll have most success growing plants like herbs and flowers or root vegetables in deep pots. These smaller kinds of greenhouses will reward strategic positioning to make use of the verticality you have on offer. If you trail them well, you could even grow cherry tomatoes in the warm months!

However, if you’re looking to grow a wider range of plants or even just more than a few pots worth, you’ll need something more like a Growzilla. The extra space makes it easier to grow a whole range of plants including everyone’s favourite, tomatoes, as well as peppers, cucumbers, and even larger plants such as citrus trees become an option.

Here is our guide for what to grow in a greenhouse with more specific recommendations based on size!

Do greenhouses need planning permission?

In general, you won’t need planning permission for a greenhouse but there are certain circumstances where you may need to check with your local authority. Provided you are under the maximum height and it does not take up more than 50% of your garden, although the rules are different in some territories such as Scotland. Check out our guide to Planning permissions for outbuildings for more details.

What types of roof are available?

Greenhouse roofs can be organised in a number of different ways, ours at present have been designed with an apex roof which helps to ensure drainage and ventilation can have the best conditions to help your building and your plants to thrive. Not to mention, the headroom is appreciated by any taller gardeners. While we may expand this in future and other competitors do offer different roofs, we’re keeping our range to what we believe will provide the best experience for our customers.

What material should my greenhouse be made from?

There are three main materials you can get a greenhouse from: Metal, Plastic/resin or Wood. While all three have their merits such as metal being extremely durable or the plastic options helping with heat retention, wood is the option we would most enthusiastically recommend. The rustic style of the timber has the strongest aesthetic appeal and is the middle ground for the benefits of durability and heat retention. Not to mention, the material is more environmentally sustainable and is a more natural fit for most gardens.

But it’s not just the frame, there’s also the element that makes a greenhouse a greenhouse: the glass! Although not every supplier will use actual glass for the glazing with many businesses now using polycarbonate or plastic for greater insulation or greater strength, but much like with our sheds we’ve chosen to use glass. Unlike polycarbonate or plastic, glass will not be damaged by UV (the main element you’ll be getting from the sunlight) and because we use 4mm thick toughened glass, you retain the strength and resistance to breaks of plastic without the discolouration risk.

Where to position a greenhouse?

Choosing a site for a greenhouse is largely down to making sure you can get maximum sunlight for the growing season. Ideally, you’d aim to get more than 6 hours of sun, this is especially important in winter where you’ll naturally have less sun to work with. If possible, trying to orient the long side East-West for maximum light can be beneficial to help catch the most light possible.

Depending on what you have in your specific garden, you will need to place your greenhouse away from large trees so that you won’t have leaves or shade block the light. In addition, you’ll want to guarantee the ground is level with good drainage. Depending on what you intend to do with the greenhouse, you may also need to make sure you’re positioned in such a way that you’ll be able to connect water and electricity. Remember as well, you need room for maintenance and cleaning so a bit of extra space will be really helpful.

Do greenhouses need a base?

As our greenhouses are sold without a floor, the subject of bases is also quite important. Once you have the location you intend to site your greenhouse, you need to decide how you want to apply the base. The benefit to having no floor is that you can also plant in the soil underneath for plants that need deeper roots but this can cause problems for stability unless you appropriately base your greenhouse as well.

To make sure the structure stays stable, the best solution is to use a perimeter base that leaves you with an edge of material so the greenhouse is off the ground but the middle if clear for your soil. Your options here are:

A concrete base, where you use paving slabs or a concrete strip around the perimeter with the greenhouse affixed to this.
A timber base, made of wood which the greenhouse can be affixed to.

While possible to put the greenhouse directly onto the ground, we would not advise this as the soil could shift as a result of water drainage or from freezing and unfreezing.

Electric heater in a greenhouse in winter

Do I need to heat my greenhouse?

You don’t have to heat a greenhouse, however without some form of heating the frame is essentially keeping what little heat it can hold in and will do little to protect plants from the cold. If you do heat your greenhouse, you can use it throughout the year and start seeding or growing temperate plants far earlier than the peak of spring.

Do you need ventilation in a greenhouse?

Ventilation is vitally important for a greenhouse as it’s the primary means to help control temperature, humidity and keep the balance of Oxygen/Carbon Dioxide perfect for your plants to thrive. There are a variety of ways to incorporate ventilation, usually with the chimney effect which uses the natural tendency for hot air to rise and thus leave via ventilation in the roof, usually via the opening of a window. While there are quite a few ways to organise ventilation, the best way to guarantee your plants have the optimal environment is to make sure you have automatic ventilation.

For our Growzilla range, we offer an automatic ventilation solution that can be set to a desired temperature and requires no power to operate. As a means to ensure your greenhouse will always have ventilation without needing constant monitoring, it’s the best solution we can advise to help ventilate only when it’s hot enough. Which is related to the next question.