Anyone looking for a simple and affordable way to get growing in their garden should consider the best plastic greenhouses. Ideal for those who don't have the means or the space for a full-size greenhouse, these plastic alternatives are surprisingly effective. They're also a wise option if you're not sure you want to invest the time, space, and money in a traditional greenhouse just yet - you can try out a cheaper plastic version to work out just how much use you'll get out of it before deciding to extend your outdoor storage space with a 'proper' glass house.
The best plastic greenhouse can help you nurture seeds and seedlings, get plants ready to be potted out, and grow veg that's happy to flourish in pots and grow bags, like classic tomatoes, cucumbers, chillies, beetroot, dwarf beans, and more. They are also an excellent option to grow your salad crops in, giving them better protection from the elements - and from common garden pests. Some gardeners like to use a smaller plastic greenhouse as a permanent undercover herb garden, ensuring their plants are warm, shielded, and at the ready to have a few stalks snipped off at any time.
Best plastic greenhouses at a glance:
• Best overall plastic greenhouse: Ohuhu Plastic Walk-In Greenhouse - View on Amazon UK
• Best small plastic greenhouse: Bramble Three-Tier Compact Greenhouse - View on Amazon UK
• Best slimline plastic greenhouse: Grow It Four-Tier Extra-Wide Grow Arc - View on Amazon UK
Like standard greenhouses, plastic greenhouses come in all kinds of sizes, shapes, and designs. It's down to you what you want to use it for and how much outside space you have to spare to work out which will best suit your needs. The most popular kind of plastic greenhouses are shelf-style versions that have a space-saving, upright design with three or four tiers, perfect to put trays of seeds or seedlings in. However, you can also get more substantial walk-in options that give you the space for even more shelving and the ability to house grow bags. We're taking a look at both types and more in our superb selection of the best plastic greenhouses currently available.
Best plastic greenhouses for your garden
Best overall plastic greenhouse
Ohuhu/AmazonOhuhu's popular greenhouse is basically a plastic replica of a traditional square glass grow house. It's constructed from a coated alloy steel frame, reinforced plastic connectors, and a transparent, thickened PVC cover. Described by several reviewers as spacious and roomy, at 1.43 metres by 1.43, this is large enough to walk into via the zippered, roll-up door that you can secure with Velcro straps. The two side windows work the same way.
Unlike some options, this comes complete with shelving - six rack-style shelves on either side offering plenty of space for plants thanks to their 10-kilogram weight capacity. This comes with ropes and stakes and has an extended base you can put weights on.
Pros
- Two Velcro side windows for ventilation
- Extended base to place weights on
- Built-in shelving supplied
Cons
- No weights supplied
Best small plastic greenhouse
Bramble/AmazonBramble offers three sizes of this shelf-style, small-scale plastic greenhouse. There are three-, four-, and five-tier versions, all of which have a 69cm by 49cm footprint. This makes this a patio-friendly choice, or if you can place it on the ground, you can use the U-shaped stakes provided on the frame's base to help keep it secure. This has a steel frame that boasts tool-free construction with many reviewers saying they managed to put it together without help from a second person.
The cover is transparent PVC with a grid design running through it to protect your plants from strong sun. This greenhouse has a roll-up door, a side ventilation flap, and two handy storage pockets on either side.
Pros
- Two side pockets for storing tools/plant labels, etc.
- Ventilation flap for air flow
- Fixing stakes included
Cons
- Door closures are not Velcro - so will take a little more time to close
Best slimline plastic greenhouse
Grow It/AmazonThis Grow It greenhouse, with its stylish, arc-shaped design and vibrant green cover, is one of the more attractive options we're featuring. This makes it a good choice if you can only place it in full view of your garden. It has a wide, slimline design, measuring just over a metre in width with a depth of 45cm. This has a strong, powder-coated metal frame and a reinforced polyethylene cover that quickly zips open and closed for easy access.
Inside the greenhouse are four shelves, perfect for smaller pots and seed trays. The shelves are removable, so you can whip one out to give your plants more growing room if required. Reviewers consider this option good value for money and are pleasantly surprised by the quality for the price.
Pros
- Attractive arc design
- Easy tool-free construction
- Internal Velcro cover fastenings for quick open and close
Cons
- No ropes/stakes included to secure it in place
Best budget plastic greenhouse
Kingfisher/AmazonThis Kingfisher greenhouse is incredibly well-rated and reviewed on Amazon with happy customer pleased with the price, ease of construction, and robust build quality. Although it's not the best-looking choice, it offers solid functionality for a very affordable price. This is perfect for anyone on a budget, or for gardeners that only want a greenhouse to use for certain times of the year - when they are germinating seeds, for example.
It offers plenty of shelf space to do just that, with four 50cm by 45cm growing platforms. The top shelf sits under the greenhouse's apex, so gives larger plants space to grow. This has a metal frame and a poly cover that features zips and the ability to roll it up.
Pros
- Simple to collapse down for storage
- Zippered door - securely closed and easy to open/close
- Apex roof for taller plants
Cons
- No ventilation flap
Best large plastic greenhouse
D4P/AmazonThis rectangular Display4Top option is similar to our overall staff pick, just larger, measuring in at a generous 1.43m wide by 2.16m long by 1.95m at its tallest point. This means there is plenty of space to be working away at planting, potting, watering, and general pottering inside the greenhouse with one reviewer confirming there is enough space for two people to work alongside each other. The larger footprint also allows for more handy shelving - there are eight wired shelves, six long shelves on either side and two smaller ones that run along the back wall.
This has an alloy steel frame and a PVC cover that's kept in place with internal ties. The zippered door rolls up and can be held in place with two ties.
Pros
- Large enough for two adults
- Eight shelves for plenty of plant storage
- Extended base for weights
Cons
- No windows, so less opportunity for ventilation
Best polytunnel-style plastic greenhouse
Smart Garden/Wickeswww.wickes.co.uk
You can get your agriculture going on with a serious, polytunnel-style plastic greenhouse. Ideal for more experienced gardeners that want to create a sheltered space to perfectly suit their growing needs, this comes as a frame and cover only, with no shelving included. This does mean, once constructed, you can tailor the inside of this greenhouse exactly as you want it, making the most of the two by three metre footprint.
The curved frame is made of metal and it's covered with extra-high density reinforced PE. This has multiple anchor points with ropes and stakes supplied. Despite its size, this boasts tool-free construction with one reviewer stating it only took them 20 minutes to construct.
Pros
- Two doors for flexible entry/exit options
- Curved roof for extra headroom
- Two windows for fresh air flow
Cons
- Shelving not supplied
Best mini plastic greenhouse
Outsunny/AmazonThis Outsunny mini greenhouse is a great half-height option for areas that wouldn't suit a taller, upright design, such as small courtyards or balconies. This does offer space for a fair few pots and trays though, thanks to its 180cm by 90cm by 90cm dimensions. While already being stable thanks to its low design, reviewers agree this has a sturdy build; a powder-coated steel frame with five cross bars and durable plastic connectors.
The anti-tear PE cover has a mesh design to offer better UV protection and stops birds - and cats, according to one reviewer - from pecking at or trampling your plants. Two sections of the cover roll up for those times you want to give your plants some fresh airflow. This can be used on the ground or over raised beds and containers.
Pros
- Can be used over raised beds
- Two roll-up sections for access and air flow
- Five cross bar construction for sturdiness
Cons
- No stakes provided
How we chose the best plastic greenhouses
All of these plastic greenhouses have been hand-selected by our team of Modern Gardens shopping experts. We carefully considered the size, design, and construction in our selection of the best. Our team has spent hours investigating and researching plastic greenhouses to make it easier for you to find the very best, and we'd never recommend a product we don't believe in.
Where possible, we also test and share the latest and best products you should know about. And with help from Modern Gardens Magazine, Garden News and Garden Answers, we share expert gardening knowledge to help you get the most from your product.
What size plastic greenhouse should I get?
This is obviously dependent on how much outside space you have and what you want to use the greenhouse for. If you know you only want a greenhouse for seed trays, one of the more compact, upright options we're highlighting will be ideal. If you want to house grow bags and pots, then you will need a more substantial structure.
"Whatever size you choose, you'll fill it up quickly, so go for the biggest model that your garden can accommodate", advises Marc Rosenberg of Garden News.
The message clearly is - if you can, go large.
Is a transparent or green PVC cover better?
Put very simply, while both types of cover will keep warmth in, a clear cover will let more light through. This means transparent is the way to go to get those seeds germinating, while green is ideal for more delicate plants that could be damaged by UV rays.
Where should I position my plastic greenhouse?
"It goes without saying, a glasshouse should be in the sunniest spot possible, but, technically, just six hours of sunlight counts as full sun, so your options may be wider than you think," states Nick Bailey of Garden News. "Aim to have the pitch facing south, to maximise light entry."
Light is the most important option to consider, but do also think about practicalities - you don't want to place your greenhouse under a spot popular with birds, for obvious reasons, and it needs to be somewhere you can easily access with a garden hose or at least, not have to go too far while lugging your trusty watering can.
How can I secure my plastic greenhouse?
The one major downside to plastic greenhouses is their vulnerability to the wind. Many of the options we're featuring here come with ropes and stakes to help secure them to the ground, but there are other things you can do to keep everything in place.
If your greenhouse is on the ground, as in lawn or earth, consider getting some U-shaped stakes to 'nail' the frame down. Rocks, or other kinds of weights, against any extended base area, are recommended, or you could even dig it into the ground.
One popular method to stop upright plastic greenhouses blowing over is to use the lowest shelf as an area to store your compost - the weight of this at the bottom of the frame should help avoid any disasters.
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Amy-Mae Turner is a Commerce Content Writer for Modern Gardens, Yours, Take A Break Pets, and A Modern Kitchen. When she's not pottering in the garden or mucking around in the kitchen, she can be found having doggy cuddles with her two beloved cockapoochis.