Join B&Q Club today for 10% off thousands of products! Already a member? Don't forget to enter your Club card number at checkout. Hurry, ends Monday!
Greenhouse buying guide
Choose the greenhouse to get planting - whatever the weather
You don’t have to be an expert gardener to get the most out of a greenhouse. These garden structures make growing and maintaining plants, fruit and vegetables easier throughout the year for everyone - from experienced growers to enthusiastic novices. Greenhouses help extend the growing season - allowing you to start planting earlier and continue later into the year. They also shelter delicate new plants from frost, snow and too much rain come the winter weather.
And it's not just about how you grow your plants, but what you can grow as well. Greenhouses provide a warm, constant climate that nurtures exotic plants that aren't native to the UK, making it possible to introduce more unusual additions to your home and garden.
So whether you're interested in your first greenhouse or replacing an existing one, read on for our guide to helping you choose the best greenhouse for your growing needs.
Before you begin
Where will the greenhouse go?
It's important to consider where you'll be building your greenhouse and there are a number of things to think about. Find a spot for your greenhouse that is:
- in the sun with no shade
- away from overhanging trees
- on level, secure ground
- easy to access from all sides of the structure (to help with maintenance and cleaning)
As well as the traditional standalone greenhouse design, we offer lean-to greenhouses. These can attach to buildings or walls - ideal if you're strapped for space.
Next up, work out how much space you have. We recommend getting the largest greenhouse you can sensibly fit. This is because larger greenhouses create a more constant climate for your plants, as it takes more time for them to heat up or cool down.
What surface will the greenhouse be placed on?
Standing your greenhouse directly on the ground allows you to plant directly into the earth. However, you may still want to lay a path through the middle as a well-watered greenhouse will soon create muddy feet.
Alternatively, placing it on a paving slab, brick or concrete base means you’ll need to use grow bags as you can’t plant directly into the ground.
Gravel is another option if you want some sort of flooring and a level of drainage. These options may also retain some heat in the summer months, ensuring your greenhouse is slightly warmer.
Will the greenhouse need planning permission?
Most of our garden buildings are less than 2.5 metres (m) tall, which means that they won’t need planning permission to be installed. However, you do need to make sure that your greenhouse is:
- only one storey and not more than 3m tall
- placed at least 2m away from any boundary
- not going to cover more than half of the land around your home
If you have any questions or doubts on building regulations, be sure to contact your local authority.
How to construct the greenhouse
Our greenhouses are available either as self-assembly or some can be assembled for you.
If opting for assembly service, your greenhouse will be professionally installed in your garden by an approved team. They’ll contact you to arrange a suitable time and date for fitting. Prepare a suitable, level base for the greenhouse before the installers arrive or they won’t be able to install.
Alternatively, if doing it yourself, we recommend asking a friend to help you install it safely – and be sure to follow the instruction manual.
Types of greenhouse
With your greenhouse's location decided on and suitably prepared, it's time to think about the different types of greenhouse available. There are two important elements to think about - the frame's material and the windows' glazing.
Greenhouse frame materials
There are three options for your greenhouse frame: aluminium, wood and extruded resin (plastic).
Aluminium frame greenhouses
Our range comes in plain metallic or green painted options, with a galvanised steel base.
Wooden frame greenhouses
Our selection of greenhouses are made with pressure-treated wood. This means that protective treatment is shot directly into the timber to prevent rot and mould. As with all wood exposed to the elements, the timber frame requires regular maintenance, such as repainting or staining every few years.
All the timber we use is approved by the Forest Stewardship Council (FSC®) – an international not for profit organisation that promotes responsible management of the world’s forests. For more information, visit our One Planet Home page.
Extruded resin frame greenhouses
A type of plastic, extruded resin frames offer an attractive and cost-effective choice that boasts better heat-retention properties than aluminium options. Slightly less robust than metal, they're best suited to smaller greenhouses.
Our extruded resin greenhouses are available in white and green finishes.
Greenhouse glazing materials
There are two main types of greenhouse glazing available - polycarbonate and glass. Some greenhouses feature more than one type to offer the best combination of insulation, lighting and safety.
Polycarbonate glazed greenhouses
A thinner, more durable option to glass, polycarbonate is available as panels or twinwall.
Polycarbonate panel glazing
Polycarbonate panels are a popular option for those on a budget and require no maintenance once installed. While offering 90% light transmission (this means it lets in almost all light), each panel has UV protection applied. This not only blocks harmful rays from scorching your delicate plants, but also prevents panels becoming discoloured over time. This high level of light transmission is ideal if you’re planting from seed.
Despite being just 0.7millimetres (mm) thick, and extremely lightweight, these panels are virtually unbreakable, making them a top choice for gardens with children and pets.
Polycarbonate twinwall glazing
Offering most of the advantages of panels with a few added benefits, twinwall is made from two sheets (walls) of polycarbonate with struts in-between. This makes it thicker than a standard panel alone, trapping the air to improve heat insulation. Twinwall looks opaque and offers 70% light transmission, giving your plants slightly more protection from the sun - best suited if you’re growing plants to maturity. Opaque glazing also ensures that the light is diffused evenly, meaning you won’t have any hotspots within your greenhouse.
Glass glazing is a heavier option for your greenhouse and choosing this will lead to a stronger structure overall. But beware of impacts, as it's more likely to shatter easily than polycarbonate. We offer two types - horticultural glass and toughened safety glass.
Horticultural glass greenhouses
For a more traditional look that lets in a lot of light, choose horticultural glass glazing for your greenhouse.
Fitted with a thickness of 3mm, this glass could shatter into large shards if impacted - something to consider if children or pets will be playing in a nearby area. However, if the glass is broken, the panes are easy to replace as they're all standard sizes.
Toughened safety glass greenhouses
For a sturdier glass option, choose toughened safety glass. It’s also 3mm thick, but is tougher and more resistant to impacts and wind than horticultural glass. And it shatters when broken, resulting in smaller pieces of glass, not shards.
Once you’ve decided on your greenhouse's materials, it’s time to think about its style elements.
Greenhouse roofing structures
There are five options when it comes to picking a roof for your greenhouse: apex, curved apex, Dutch apex, cathedral and lean-to.
Whichever option you choose, check to see if it comes with a roof panel that you can prop open for extra ventilation. This also releases any condensation without losing as much heat as you would by keeping the doors open.
Apex roof greenhouses
The traditional pointed greenhouse roof, the apex is shaped like an inverted “V”. Choose an option with built-in guttering and collect rainwater to use around your garden.
Also available are curved apex roof greenhouses. These offer the same benefits as the apex while the softer lines lend a more contemporary look.
Dutch apex roofs are also known as the Dutch barn or barn roof. This design boasts greater height - ideal if you want to grow taller plants in your greenhouse.
And for larger spaces, consider a cathedral roof. This style maintains the apex roofing structure, but the floor design is larger, creating a P shape rather than a simple square or rectangle.
Attaching to the side of your home or a wall, lean-to greenhouses look like half of a traditional structure. Because of this, they're reminiscent of conservatories and can take up the least amount of space, making it perfect for patios. Lean-to greenhouses can have a number of apex roofing styles.
If placed up against a property, heat may radiate out and into your greenhouse. So be sure to take this into account when choosing which plants to grow in there – some may not suit the higher temperature.
Before choosing your greenhouse door, consider how much space you’ll need to open it up fully. Will you be moving large items in and out, such as tall plants, tools or equipment? And don't forget ventilation – the bigger the greenhouse, the more ventilation it will need. Think about both the number of doors needed and the most suitable opening mechanism.
Number of greenhouse doors
Choose between single and double greenhouse doors.
Single door is the more traditional option - great for smaller spaces.
Double greenhouse doors offer the most ventilation, as well as easy and convenient access if you need to move larger items in and out.
Opening style of greenhouse door
Again, there are two opening styles on offer - sliding and hinged greenhouse doors.
Sliding doors (pictured) are a great space-saving option. They're made from glass, but don’t worry about them swinging open and smashing against anything – the rails ensure limited movement.
Hinged doors are made from polycarbonate glazing. All of our hinged doors come with magnets on the corner of their frames so that they can be held in place while open. There's still the risk of them catching in the wind, so be sure to keep an eye on them when there’s blustery weather.
You might need
With your greenhouse chosen, don’t forget the finishing touches. We offer a wide range of greenhouse accessories to suit your growing needs.
Greenhouse bases help attach your greenhouse to the surface beneath - be it just bare ground, paving, brickwork or concrete - ensuring that it’s secure.
Some of our greenhouses come with bases as part of the package, while others don’t so be sure to check yours before buying. We offer plastic bases separately, as well as anchor kits.
Greenhouse staging and shelving
Keeping your plants organised will enable you to grow more, as well as group them into different stages. Do so with our range of staging and shelving.
Choose between plastic and metal options to help you keep your growing workspace tidy.
Ventilation is important for your greenhouse plants in order to keep the humidity down. And we offer auto vents and louvre windows to make this even easier.
Most greenhouse frames include adjustable air vents, but an auto vent responds to weather changes and automatically opens and shuts the windows accordingly. No power supply is required to keep the air circulating and best of all, you don't have to worry about doing anything yourself.
Louvre windows (pictured) offer adjustable ventilation through the side panels of your greenhouse, giving you another way to provide much-needed ventilation.
If you’re concerned about how much light is getting into your greenhouse, add a shading kit.
This synthetic green netting protects delicate plants from the intense rays of the sun, but doesn't block out light. A must-have when temperatures soar in summer.
When winter arrives it's essential to protect your greenhouse plants. Greenhouse bubble insulation, also known as garden bubble wrap, does the job - retaining heat and protecting plants from frost in your greenhouse. It still lets in sufficient light and can help keep heating costs down.
Simply cut to size and attach.
Depending on the plants you want to grow (especially tropical types), you may need to heat your greenhouse to get it to the right temperature. Invest in a paraffin heater to keep the space as warm as you require.
And it's not just about the plants. Having a heater in your greenhouse can help keep you toasty and comfortable while working in your greenhouse. This can be especially important when the temperatures drop in autumn and winter.
Make the most of the unpredictable British weather by collecting rainwater to use in your greenhouse. It will save you from having to walk up and down the garden with a watering can, or unrolling the hose – and is the ideal choice in case of a hosepipe ban.
Most aluminium greenhouses come with guttering built-in, so add a rainwater diverter and you can direct the water from the guttering into a water butt or container.
And if you’re going on holiday, or you don’t want to water every day, consider installing a water dripper system and timer. This will ensure that each plant is watered automatically and at your preferred time of the day.
Greenhouse maintenance and repairs
You won’t need to do much to keep your greenhouse looking great for years to come. Simply using the right tools and materials to keep the frame clean will ensure that rot or rust won’t cause it to deteriorate.
Clean aluminium and extruded resin frames with a pressure washer or simply scrub clean with an outdoor disinfectant, such as Jeyes fluid, on a brush or cloth. Wooden frames need to be regularly treated with a stain or oil to prevent rot or mould.
And if you need to replace any glazing, pick up our maintenance kit or glazing clips to help secure the new glazing in place.