an aluminium greenhouse full of plants

A greenhouse is one of the best investments you’ll ever make for your garden. It offers you the chance to extend the growing season, increase your range of homegrown produce and cultivate plants not normally suited to the British climate.

A greenhouse also makes an excellent focal point in the garden, a central hub in which to potter around and plan your yearly gardening tasks.

2 women tending to plants in a small, green greenhouseDepending on its size, a greenhouse can be a major financial investment. However, it is one which is worth every penny because it will bring you decades of enjoyment. With this in mind, you need to do your homework before choosing your ideal greenhouse so that you make the correct decision first time round.

We don’t want you to be the person who looks at their newly assembled glasshouse and says, ‘if only I’d thought of that first’.

This is why we’ve put together a comprehensive greenhouse buying guide, where we pose the 10 key questions that you need to ask yourself before purchasing your new greenhouse.

10 Questions to Ask Yourself Before Buying A Greenhouse

1. What Sized Greenhouse Should I Buy?

10x20 greenhouse with a black aluminium frameThe short answer to this question is the biggest one possible.

We’re yet to meet a gardener who wishes they didn’t own a bigger greenhouse. Gardening is as addictive as it is rewarding and this means you’re going to fill your greenhouse quickly.

Of course, you’ll need to ensure that you have enough room to easily access your greenhouse, as well as maintain it. With the exception of lean-to greenhouses (more of them later), it’s a good idea to leave at least the width of a wheelbarrow between the sides of your greenhouse and any nearby walls, fencing, hedges and trees. This gives you room to clean the glazing, treat the wood (if applicable) and carry out any repair work. Also, be mindful that doors and vents must be able to open freely.

Once you’ve factored all that in, and remembered to leave enough space for your other garden-based activities too, go large with your choice of greenhouse – as large as you can.

2. Where Should I Position My Greenhouse?

a 6x4 greenhouse with an aluminium frame and open roof ventIdeally, you should position your glasshouse in the part of your garden which enjoys the most hours of sunshine throughout the day.

A spot sheltered from cold northerly winds is also a good idea.

As touched on in the previous question, think about space too. Be sure that you can still comfortably tend to your hedges, trees and plants. It’s no good buying a greenhouse only to neglect the other greenery in your garden.

If you have a smaller outside area, you’ll be particularly keen to position your glasshouse so that you can make the most of your garden space. This brings us nicely on to the next major consideration…

3. Which Greenhouse Design Should I Choose?

Most people consider there to be two main greenhouse designs: traditional and lean-to.

Traditional Greenhouses

a traditional wooden greenhouse full of plantsTraditionally-shaped greenhouses resemble most other garden buildings in that they are designed with four walls, and gables which lead up to an apex-style pointed roof.

There are slight variations on this theme, of course, with some (usually larger) greenhouses having more rounded contours where the walls meet the roof, or even angled panels joining the two.

Traditional greenhouses look superb, as long as you have plenty of garden space.

Lean-To Greenhouses

a 6x2 lean-to greenhouse with a green aluminium frameAs the name suggests, lean-to greenhouses are designed to lean or rest against a flat surface, usually a wall or fence. They have a pent-style roof which slopes downwards, away from this structure.

Due to their space-saving designs, lean-to greenhouses are often popular with people who have smaller gardens, although larger models, known as sunrooms and resembling conservatories, are big sellers too.

Greenhouses with Innovative Designs 

a tall wooden greenhouse with a small footprintThe greenhouse world doesn’t completely revolve around traditional models and lean-tos. There are plenty of innovative designs available, including hexagonal greenhouses and taller models with small footprints and multiple doors.

Again, these types of greenhouse are ideal if your garden space is at a premium.

4. Do I Need A Greenhouse Base?

We’ll come to the greenhouse base next because this is something you’ll need to organise before your greenhouse is delivered.

A greenhouse base is absolutely essential to the functionality and longevity of your greenhouse, so do not, under any circumstances, try and do without one.

The only thing you need to decide on is whether to build the base yourself or buy a readymade one.

Building A Greenhouse Base

a man building a concrete greenhouse baseIf you enjoy practical tasks, go for it…

It’s a good idea to raise your greenhouse base a few centimetres above ground level. This helps prevent ground moisture from damaging the frame and ensures the doors can open freely.

Concrete slabs, laid wet or dry, make a sound base as they are solid, level and stable. They can also be watered in hot weather to add moisture to the greenhouse.

Perimeter Bases

Some gardeners prefer a perimeter base only, which allows for planting directly in the ground inside the greenhouse. If you choose this option, be aware that rodents can burrow into the greenhouse.

Please note that perimeter bases are sometimes supplied with the greenhouse itself, so don’t go to any unnecessary trouble building one before you choose your new greenhouse.

Readymade Greenhouse Bases

a plastic greenhouse base on a lawnWe stock a range of readymade, plastic greenhouse base kits, available in all of the popular greenhouse sizes. The obvious advantage to these bases is that they are far easier to lay than concrete slabs.

They consist of a heavy-duty membrane and interlocking plastic grid system, which should be filled with gravel. The end result is a highly-effective and attractive base for any glasshouse.

5. Which Type of Greenhouse Frame Is Best?

The major choice here is between aluminium and wood.

Aluminium Frames

a 6x10 greenhouse with a black aluminium frameThe majority of modern greenhouses have an aluminium frame. The main advantages to this type of frame are that they are robust, durable, maintenance free and resistant to rust.

More often than not, greenhouse aluminium frames are silver in colour, although powder-coated finishes in green or black are becoming increasingly popular.

Aluminium greenhouses generally have guarantees ranging from 5 to 12 years.

Wooden Greenhouses

a 10x8 wooden greenhouse with double doors and a roof ventNothing beats the charm of a wooden greenhouse. They are incredibly attractive and blend in perfectly with the natural environment of a garden.

Of course, there’s the option to paint a wooden frame too, and create a completely unique style to complement a particular theme in your garden.

Pressure treated timber frames usually come with a 15-year anti-rot guarantee, so no further treatment is required, saving time and money. This makes them almost as low-hassle as their aluminium counterparts.

Dip treated wooden greenhouses usually have a 10-year anti-rot guarantee, but will require annual retreatment to validate the guarantee.

Considering the amount of glazing on a greenhouse, this process is usually a more time-consuming job than treating a shed. It is obviously something to think about carefully, and reinforces our advice about leaving sufficient space to access the entire perimeter of your greenhouse.

The one advantage of a dip-treated frame over a pressure-treated frame is that the greenhouse is normally cheaper.

6. Any Preference on Greenhouse Glazing?

There are four major choices with greenhouse glazing: horticultural glass, toughened glass, styrene and polycarbonate.

Horticultural and Toughened Glass

a 6x6 glasshouse with an aluminium frame, sliding doors and open roof ventGlass lets in 90% of sunlight and radiates heat back into the greenhouse. This makes it a very efficient glazing option. However, it is relatively fragile compared to other materials.

So, if you want a real glasshouse and have a busy garden, particularly children who enjoy ball games, we advise upgrading to toughened glass. It’s more expensive, yes, but in the long run definitely worth it.

Styrene and Polycarbonate Greenhouse Glazing

an 8x8 greenhouse with frosted polycarbonate glazingStyrene is far lighter in weight than glass but incredibly tough; in fact, it is virtually unbreakable. This makes it a safer option for those of you with pets and children. Providing that it’s UV-stabilised, it will retain its crystal-clear appearance and will neither fade nor discolour in the sun. It’s a very good option.

Polycarbonate greenhouses tend to come with aluminium frames. Like styrene, the glazing is virtually shatterproof and completely UV-stabilised.

Its exact type and thickness can vary between greenhouses. Generally, thicker and/ or frosted polycarbonate glazing means slightly lower light transmission but greater protection from harmful UV rays and superior light diffusing properties, which prevent your plants from getting scorched.

Light transmission levels in polycarbonate greenhouses range between about 80 and 90%. Do not be influenced by the differences in these figures as all of our polycarbonate greenhouses are excellent buys.

7. What About the Greenhouse Doors?

The main choices here are between a single or double door, conventional or sliding opening, and whether or not to have a threshold bar.

Single or Double Doors

On a small greenhouse, a single door will probably be sufficient. Double doors tend to provide easier access, of course, which is ideal if you’re housing large potted plants, going backwards and forwards with a wheelbarrow, or if you’re a wheelchair user.

Sliding Doors

Sliding doors come into their own when your greenhouse is in a relatively confined space. Also, there’s no real danger of them blowing shut in windy conditions.

a small wooden greenhouse with a single doora greenhouse with a black frame and sliding double doorsthe low threshold on an aluminium greenhouse

Threshold Bars

If you have mobility issues, particularly if you are a wheelchair user, you should opt for a greenhouse without a threshold bar. This will give you easier, safer access to your greenhouse.

Lockable Doors

The only other door-type consideration is whether or not you want to be able to lock it. Valuable garden tools and, to a lesser extent, invaluable garden plants can be attractive to thieves. If this concerns you then choose a greenhouse with a lockable door.

Of course, if you’re buying a lean-to greenhouse/ sunroom and it can also be accessed directly from your home’s back door, you will opt for a lockable door.

8. Why Is Greenhouse Ventilation So Important?

Vents and Louvre Windows

The vent is an essential part of a greenhouse because it allows you a degree of control over the temperature inside the greenhouse. Vents are generally located on the greenhouse roof, with louvre windows/ vents positioned on the side panels as an added bonus to further enhance airflow.

Generally, the larger the greenhouse, the greater the number of vents, although some small greenhouses do have multiple vents or a vent and side louvre window, which is a big selling point. All other things being equal, choose a greenhouse with as many vents as possible.

a greenhouse louvre windowa greenhouse with a green frame and 2 open roof vents

Automatic Vents

Another big decision you will need to make here is whether to pay the extra for auto vents.

As the name suggests, they open and close automatically when the temperature inside the greenhouse rises or falls to a certain level. Automatic vents are not essential but are nice to have, being particularly useful if you are absent from your greenhouse for large parts of the day.

9. Do I Need Greenhouse Staging/ Shelving?

Yes, you certainly want a greenhouse with staging and shelving.

Greenhouse Staging

Staging is an essential component of a greenhouse because it gives you a raised surface on which to pot plants, care for them and carry out other gardening-related tasks.

a seed tray and gardening tools sat on green greenhouse stagingheavy-duty greenhouse shelving

Greenhouse Shelves

Shelving is equally valuable, as it helps you maximise your available greenhouse space. Without it, you would only be able to use the floor.

When you consider the room required for compost, empty pots and tools, a greenhouse without shelving doesn’t leave much room for plants.

10. What Essential Greenhouse Accessories Should I Buy?

Regarding Temperature

Thermometers

To ensure you have a suitable growing environment for your plants, you need to be aware of the temperature. This makes a thermometer a must.

All thermometers provide a current temperature reading, but one which shows the daily minimum and maximum temperatures too is best because it helps you properly monitor, and so optimise, growing conditions throughout the day, even when you’re not around.

Roller Blinds

The level of shading plays a big part in determining the temperature inside a greenhouse. There are a variety of ways to achieve this, roller blinds being one of them.

Blinds look great and can even be linked to a thermostat. Again, this allows you to optimise growing conditions, even when away from the greenhouse.

a stainless steel greenhouse heaterGreenhouse Heaters

Even though the temperature inside a greenhouse is warmer than outside, there are plenty of times over the course of the year when plants need that bit of extra heat.

Electric greenhouse heaters and portable gas cabinet heaters are both effective.

Although your choice will probably be influenced by whether or not your greenhouse is connected to a power supply, a big advantage with gas heaters is their manoeuvrability.

Regarding A Water Supply

Along with light and heat, plants need water. You shouldn’t have any problems supplying them with this, but consider the benefits of purchasing the following 3 greenhouse accessories:

Greenhouse Guttering

Some greenhouses are supplied with an integral guttering system – problem solved.

If not, you would be well advised to purchase one.

We recommend Hall’s Rainsaver Guttering, which is available in all of the popular greenhouse sizes, very easy to install and comes with everything required to connect it to a water butt.

a greenhouse/ shed guttering kita water butt

Water Butts

An external water butt allows you to harvest rainwater for the benefit of your plants. The water is obviously free, sustainable and better for your plants than what comes out of the tap.

Water Tanks

A water tank in a greenhouse has two useful functions.

Firstly, the water it provides is slightly warmer than tap water, and this makes it less of a shock to your plants’ systems.

Secondly, the slight evaporation of the water will raise humidity levels within the greenhouse and reduce water loss from your plants’ leaves.

In terms of size, it depends on how big your greenhouse is but even a small tank tucked into a corner, big enough to dip a watering can into, is a great addition…but don’t let it take up too much valuable growing room!

Regarding the Plants

seedlings in plant potsPots

You can never have too many pots. Plants grow quickly and it’s important to give them a suitably-sized home.

Trellising Kits

Climbing plants are one of the most beautiful sights in a garden and there will be times when your young climbers need the protection of a greenhouse. A trellising kit is ideal for this purpose.

Once You’ve Chosen Your Greenhouse

Assembling Your Greenhouse

Once your new greenhouse has been delivered, choose a dry day to assemble it and start early.

For anything but the smallest greenhouse, it is a two-person job so enlist some help.

Lay out all of the parts, identify them and ensure you have the correct tools to hand. This done, you can reasonably expect to own a fully functioning by the end of the day.

What to Grow?

an assortment of plants in a greenhouseAnd this is when the joys of greenhouse gardening properly begin:

From all of us at Shedstore – happy gardening.

Greenhouses for Sale

a woman inside a fabric greenhouse, which has a steel frame

We hope you've found this blog informative and that it has made you feel more confident about choosing your dream greenhouse. When you're ready to make that choice, have a look through our full range of greenhouses for sale to find the greenhouse that's right for you.

Need More Help Choosing Your Greenhouse?

Our friendly, UK-based customer service team will be happy to answer any questions you have about greenhouses. You can contact them by telephone on 0333 003 0518, by live chat on the website, or by emailing us at [email protected]



Top image: 6'4 x 10'6 Halls Popular 106 Greenhouse