Garden & Lawn

Top 4 Best Lean-to Greenhouses – Buyers Guide & Reviews

Last updated on May 3rd, 2021

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If the only reason that you don’t have a greenhouse is that you don’t think you have the space for it, take a look at these lean-to greenhouses. These outdoor growing structures do the same tasks as their larger alternatives but take up much less space. All you need is a straight and stable wall that’s high enough to act as the back wall of the greenhouse, and enough ground space for the greenhouse to stand on. If you use a garage or house wall, you’re also conveniently near to water and electricity outlets. And once the plants are all out of the greenhouse, use it as a mini sunroom.

lean to greenhouse options

Our review looks at a variety of sizes and models of lean-to greenhouses. Almost of them are made of aluminium making them lightweight and long lasting. The other models are constructed from wood for those who like their garden structures to be of natural materials and from resin for those who love modern materials. We identify the pros and cons of each model and discuss their best features in more detail.

Our Buyers Guide takes you through the different parts of a lean-to greenhouse and explains some of your different choices.

Our Best Pick for lean-to greenhouse is the BillyOh Polycarbonate Aluminium Metal Frame Lean-To Greenhouse. This is the only greenhouse in our review to come with its own base, saving you the trouble of building a foundation to anchor the structure down on

The Runner-up in our selection is the Waltons Wooden Lean-To Greenhouse. Constructed of Forestry Stewardship Certified timber, this greenhouse is an attractive combination of wood cladding and semi-transparent glazing.

Best Pick

BillyOh Polycarbonate Aluminium Metal Frame Lean-To Greenhouse
The BillyOh Polycarbonate Aluminium Metal Frame Lean-To Greenhouse (4ft x 8ft) is large enough to provide sufficient growing space for the average home gardener yet has a small footprint so that it fits snugly against a garage or house wall. Its green powder-coated aluminium frame looks good against any brick wall, while the included base means that you don’t have to worry what ground surface the greenhouse stands on, as long as it’s level. The sliding door is a space saver and the vent in the roof allows for optimum air ventilation and circulation for your tender plants. This is a great lean-to greenhouse if you want to start your own seedlings but have limited garden space to put up a regular greenhouse.

Runner-up

Waltons Wooden Lean-To Greenhouse
The Waltons Wooden Lean-To Greenhouse 4ft x 8ft offers many of the same features as our Best Pick but it’s built of a natural material for those who like a more rustic look to their garden landscape and structures. The 4ft by 8ft growing area is ample space for starting seedlings for the average home garden. Use the roof vent and the swing door for air circulation and ventilation to create the perfect interior environment for your plants. You do have to create your own base to put this lean-to greenhouse on, one that can drain excess water away quickly and stay level. If you like stylish garden structures of natural materials, this is a good choice for your greenhouse.

Top 4 Best Lean-to Greenhouses Review

1. BillyOh Polycarbonate Aluminium Metal Frame Lean-To Greenhouse (4ft x 8ft) 

Best Pick

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BillyOh Polycarbonate Aluminium Metal Frame Lean-To Greenhouse

The BillyOh Polycarbonate Aluminium Metal Frame Lean-To Greenhouse is a standard size greenhouse that offers plenty of space for the average home gardener to start their seedlings early in the spring. Its smooth green finish fits into any garden landscape and looks professional. This is the only model in our review that comes with its own base (of galvanised steel) so you don’t have to worry about anchoring the greenhouse frame down on to the ground.

Another benefit of this BillyOH lean-to greenhouse is that it has a sliding door in one of the end walls. A sliding door saves space both inside the greenhouse and outside in the garden as it doesn’t swing open like a regular door. All the walls and the door are made of double-layered polycarbonate plastic glazing. This provides great insulation as well as protection from most harmful UV-rays. With the use of the roof vent that allows air circulation, the growing environment inside the greenhouse is better suited to your plants than outside in your flower and vegetable beds.

Stability is important with an aluminium-framed greenhouse as this is a lightweight metal. Once you’ve secured the base to the ground, you don’t have to worry with this model as the structure has extra aluminium roof and wall struts to keep it upright and in alignment. This is important as many cheaper alternatives save money by not having what you might consider enough struts.

As with any lean-to greenhouse, the BillyOh Polycarbonate Aluminium Metal Frame Lean-To Greenhouse comes with many parts to put together. Unfortunately, online reviews say that the assembly instructions are poorly written which from our experience is nothing for greenhouse instructions, so be sure to double-check that you do have all the necessary fixtures and fittings before you start the installation process.

Pros

  • Walls are made of two-layered semi-opaque polycarbonate glazing protected from UV rays.
  • Aluminium frame is lightweight and rust proof for longevity and weather-proofness.
  • Roof vent allows the air to ventilate inside and fully circulate around the plants for a healthy environment.
  • Base is galvanised steel so you can place the greenhouse anywhere with destroying the surface.
  • Door slides open and doesn’t take up space inside the greenhouse or outside in your garden.
  • Stability guaranteed by extra roof and wall struts.
  • Dimensions: 1.25m (width); 1.92m (internal depth); 1.35m (lower height); 2.21m (height at wall).

Cons

  • Assembly instructions are difficult to follow.

Our recommendation

The BillyOh Polycarbonate Aluminium Lean-To Greenhouse is a small enough greenhouse to fit against most house and garage walls yet still provides adequate growing space for the average home gardener. Its smooth green powder-coated aluminium frame fits into any garden landscape and the sliding door gives you more space inside and outside the structure, lessening its footprint. The included galvanised steel base means that you just have to level out the ground beneath the greenhouse rather than building an appropriate floor surface.

We’ve made the BillyOh Polycarbonate Aluminium Metal Frame Lean-To Greenhouse (4ft x 8ft) the Best Pick of our review. It has all the features, and a polished finish, that you need in a space-saving lean-to greenhouse.

This lean-to greenhouse is for you if you’ve always put off buying a greenhouse due to lack of space and want one that is both functional and looks good.


2. Waltons Wooden Lean-To Greenhouse 4ft x8ft

Runner-up

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Waltons Wooden Lean-To Greenhouse 4ft x8ft

The Waltons Wooden Lean-To Greenhouse is an alternative to our Best Pick. It’s the same size but this one has a wooden frame instead of aluminium which many people prefer. The lower one-third of the walls and the door are constructed of 12mm tongue and groove cladding made from Forestry Stewardship Certified wood. This gives your lean-to greenhouse both rustic style and some interior privacy. You can leave a clutter of gardening tools on the floor and no-one outside will know.

The FSC-certified wood has a 10-year anti-rot guarantee which offers peace of mind for a whole decade of growing plants. To validate this warranty, however, you need to put a high-quality preservative on all the timber before you start to use your greenhouse and once a year afterwards. Make sure that the preservative is also waterproof.

We recently took a look at some good paints that might just do the job here.

The polystyrene glazing has a coating to protect the plants from harmful UV-rays and to stop the window material from becoming brittle. The manufacturer also recommends sealing the windows to offer protection from water leaking in. This may seem like a lot of extra work, but at least you’ve been forewarned about what you need to do to make the structure waterproof. Don’t forget if you plan on heating your greenhouse, filling in any gaps is something you will need to do anyway if you want it to be as efficient as possible,

This Waltons Wooden Lean-To Greenhouse does not have a built-in base. This means that you have to provide the floor surface yourself. Choose one that can drain away from the excess water from your plant watering sessions, can be easily levelled and that you can stand comfortably on for the many hours you enjoyably spend with your plants.

Pros

  • Wooden lean-to greenhouse with FSC certified timber panels on the lower one-third of the walls for style and privacy.
  • Anti-rot guarantee for 10 years on all the timber parts covers a long life of growing plants.
  • Single vent on the roof opens like a window to provide air circulation for strong and healthy plants.
  • Single door is the same wood and glazing style as the walls for a cohesive design.
  • Polystyrene glazing has UV protection for stability from the sun’s rays and for long life.
  • Dimensions: 2.44m (width); 1.22 (depth); 1.86 (height at wall).

Cons

  • Comes without a built-in base.

Our recommendation

The Waltons Wooden Lean-To Greenhouse 4 ft x 8ft is an alternative to our Best Pick, the BillyOh Polycarbonate Lean-To Greenhouse, for those who prefer their garden structures to be made of natural materials. This wooden lean-to greenhouse offers the same growing space but in a more rustic style.

The FSC-certified timber comes with a 10-year anti-rot guarantee as long as you apply wood preservative at the beginning and every year thereafter. There’s the usual vent in the roof and door at one end for ventilation and air circulation. You do, however, have to provide your own base and to be sure to anchor the frame to the ground. Ideally, you want to stand it on a hard surface or build a brick base around the edge of the greenhouse to stop it rotting if you want to plan in the ground inside the greenhouse.

The Waltons Wooden Lean-To Greenhouse is our Runner-up selection. It provides an alternative selection in wood for those who prefer a natural or rustic look to their garden landscape. 


3. Palram Rion Lean-to Greenhouse 6ft x 10ft

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Palram Rion Lean-to Greenhouse 6ft x 10ft

The Palram Rion Lean-to Greenhouse 6ft x 10ft is the largest structure of the greenhouses in our review. It’s also the only lean-to greenhouse whose frame is made of white, thick extruded resin. This makes it a very sturdy greenhouse, both in looks and in stability.

The resin frame has a UV-protection coating that gives 100% protection from the plastic becoming brittle over time. The resin also serves as insulation for the interior of the greenhouse which is important. The glazing panels for the walls are made from 3mm transparent acrylic that let the maximum amount of light (90%) through to keep your plants readily growing. 

The roof panels are made from 4mm polycarbonate plastic that are ridged and opaque and serve as extra insulation for the air inside. The roof panels are pretty much unbreakable and can hold heavy loads of snow in the winter so you don’t have to worry about removing the snow too often in winter.

The vent on the roof and the single door work together or apart to keep the air moving through the interior space for your plants’ good health. However, you do need to provide a base for the greenhouse to stand one, one that drains water away and remains level.

Putting together this significant structure is done by using “snap and go” connectors. Unfortunately, online reviewers say that this is not nearly as easy as it sounds. Quite a few frustrated users say that this greenhouse is difficult to put together even by DIY experts; one person says that people who handle technically oriented drawings will be OK with the assembly. So make sure to enrol anyone you know who has mechanical assembly skills, patience and quite a bit of free time. Failing that give yourself plenty of time and have plenty of patience.

Pros

  • Lean-to greenhouse with a white extruded resin frame offers insulation on those cooler nights.
  • The frame and the glazing panels are all 100% UV protected to preserve the integrity of the materials yet allow sunlight to reach your plants.
  • Roof panels are made of Twin wall, 4mm polycarbonate plastic and give excellent heat insulation.
  • Side panels are from 3mm transparent acrylic to let the maximum amount of light in for your growing plants.
  • Easy to assemble with “snap and go” connectors.
  • Window-like vent on roof and single door allow for air circulation and ventilation for an optimal internal growing environment.
  • Dimensions: 3.24m (width); 2m (depth) and 2.47m (height at wall).

Cons

  • Some may find it a little difficult to assemble.
  • Comes without a base.

Our recommendation

The Palram Rion Lean-to Greenhouse 6ft x 10ft is a sturdy greenhouse that takes insulating its interior space seriously. Once you have assembled the structure (and that’s reported to take a while) you can leave it out in all seasons as the roof holds a heavy load of snow safely. Although the structure is built of resin (a type of plastic), everything has been 100% UV-protected so should not become brittle over time. The acrylic panels on the walls let through 90% of the sunlight to encourage your plants to grow strongly and healthily.

We recommend this lean-to greenhouse for those who have the wall space to accommodate it and the desire for a large and serious greenhouse. The Palram Rion Lean-to Greenhouse doesn’t compromise any of the quality of a regular greenhouse just because it fits up against a wall.


4. TecTake Lean-to Greenhouse 6 x 4ft

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TecTake Lean-to Greenhouse 6 x 4ft

At the other end of the size scale to the previous model we review is the TecTake Lean-to Greenhouse 6 x 4ft. This is the smallest greenhouse in our review and shows that even those with really limited outdoor space can also have the pleasure of growing their own plants from seeds or cutting it simply overwinter a few tender plants.

This greenhouse is just a miniature version of the larger ones in our review. It has an anodised aluminium steel frame and semi-opaque 4mm hollow-chamber polycarbonate panes. These add up to a lightweight greenhouse so be sure to anchor it firmly to the ground as it doesn’t come with its own base. The manufacturer recommends concreting it into the ground. However, if you don’t want to make this greenhouse a permanent structure in your garden, be very careful to anchor the frame firmly to the ground and the glazing panes firmly to the frame.

The roof has the usual vent that opens like a push-out window for air circulation and ventilation for a healthy interior environment. The single door slides open, not taking up space inside and preserving the small footprint outside the greenhouse.

Pros

  • Lean-to greenhouse with a stable anodised aluminium frame with a small footprint for those with limited outdoor space.
  • Glazing is with 4mm hollow-chamber polycarbonate panes that are ridged and provide ample insulation for tender plants.
  • Air circulation and ventilation is through a roof vent that operates as a window.
  • Sliding door is easy to open and doesn’t take up any space inside or outside the greenhouse.
  • Dimensions: 1.92m (width); 1.28m (depth) and 2m (height at wall).

Cons

  • Comes without a base.
  • As with most greenhouses, you may find the instructions are difficult to follow.

Our recommendation

The TecTake Lean-to Greenhouse 6ft x 4ft is just a regular lean-to greenhouse but in miniature. The anodised aluminium frame and polycarbonate semi-opaque glazing panels add up to a lightweight structure that you must just be sure to anchor firmly to the ground, as this model doesn’t come with a built-in base. Air circulation is provided by the push-out roof vent and the single width space-saving sliding door.

We recommend the TecTake Lean-to Greenhouse 6 x 4ft for anyone who believes that they really don’t have the outside space for a greenhouse. You too can be one of the gardeners excited in the early spring as they sow their own seeds to start their plants.


Buyer’s Guide

Buying a lean-to greenhouse is similar to purchasing a mini greenhouse or a full-size one, except that receive only three walls. You supply the fourth one yourself, usually in the form of a brick wall of your house or garage.

In this Buyer’s Guide, we introduce the other elements of a lean-to greenhouse and discuss what to look for.

Frame

As with other greenhouses, you have a choice of material for the frame of lean-to greenhouses. 

Aluminium frames are most popular as they’re lightweight. If powder-coated, are rust-resistant. Just be sure to repaint the metal if the powder-coating becomes chipped or flakes off as the exposed metal will rust. 

Steel frames are heavier and more durable and these may also be powder coated. Powder coating metals gives manufacturers the opportunity to colour the frame, usually in a colour (for example, green) that suits most garden landscapes.

lean to greenhouse frame types

For those who prefer natural materials for their garden buildings, wood frames are another option. Make sure that the timber has been certified by the Forestry Stewardship Council if you’re concerned about using sustainably produced woods.

Also check the anti-rot warranty that comes with your purchase to see if you have to abide by any rules to qualify; for example, you may have apply timber preservative to the wood parts of your greenhouse annually. 

One of the greenhouses we review offers yet another choice of frame material – extruded resin. This is a thick, solid type of plastic that is both sturdy and long-lasting, as long as it has received a coating for UV protection.

Glazing

Glazing refers to the transparent, semi-opaque or opaque materials used on the walls and roof of the greenhouse. All the greenhouses we review here use some form of plastic as the glazing material. 

lean to greenhouse frame types

Polycarbonate safety glazing is difficult to break and can sustain quite a heavy load of snow in the winter. Two sheets are often layered together for extra strength and insulation. 

Polystyrene is not as strong as polycarbonate but is still several times stronger than glass. It’s usually clear and is also a popular choice for greenhouse glazing. 

None of the lean-to greenhouses we review uses standard horticultural glass, this is fairly common with domestic greenhouses as they are easier to break.

Ventilation and entry

All greenhouses have a roof vent of some sort. All the lean-to greenhouses in this review have a single roof vent that opens like a push-out window. This lets in air for ventilation and circulation. You choose how far you want to open the vent and so the amount of air that flows in. 

Check out our review of the best automatic greenhouse vent openers here

lean to greenhouse frame types

You can also open the door for air circulation as well as to enter the greenhouse. The doors in the models we review are all single width. In general you choose which end of the greenhouse to install the door and which side it opens to. Swing (regular) doors usually open outwards so as to not take up any space inside the greenhouse. Some greenhouses we look at have sliding doors; these doors slide to the side and so don’t increase the footprint for the length of the greenhouse.

Base / flooring

Only our Best Pick, the BillyOh Polycarbonate Aluminium Metal Frame Lean-To Greenhouse , comes with a base. In this case, you secure the base to the ground and then the frame to the base. This gives extra stability to the greenhouse as well as  providing a tidy floor. For all the other models, you need to provide your own level and easily drained base on which you can anchor and stand the greenhouse.


Final Conclusion

Growing your own plants, herbs, vegetables and fruits from seeds and cuttings is one of the immense joys of having our own garden. Lean-to greenhouses bring this in reach of everyone, regardless of the size of their outdoor spaces. Taking up spaces from 4 feet by 6 feet up to more than 6 feet by 10 feet, as long as you have a stable wall that’s long and high enough, these compact greenhouses give you the controlled interior environment you need to start the growing season right.

We chose the BillyOh Polycarbonate Aluminium Metal Frame Lean-To Greenhouse as our Best Pick. This is a lean-to greenhouse that suits most people’s needs. Its smooth green finish fits into any outdoor environment.

The Waltons Wooden Lean-To Greenhouse is our choice for Runner-up. It’s wood cladding construction adds a rustic touch to a garden as it delivers just the space you need to start your seedlings.

Once you’ve chosen your lean-to greenhouse you need to set up its interior in the most efficient way to accommodate everything you want to grow. Our Best Greenhouse Staging and Shelving Products to Organise Your Greenhouse review tells you about the latest products to do just that.

If you still want a small greenhouse but don’t necessarily need a lean-to one, check out our review on stand-alone mini greenhouses.


Last update on 2021-09-14 / Affiliate links / Images from Amazon Product Advertising API

Welcome to my site, my name is John and I have been lucky enough to work in horticultural nurseries for over 15 years in the UK. As the founder and editor as well as researcher, I have a City & Guilds Horticultural Qualifications which I proudly display on our About us page. I now work full time on this website where I review the very best gardening products and tools and write reliable gardening guides. Behind this site is an actual real person who has worked and has experience with the types of products we review as well as years of knowledge on the topics we cover from actual experience. You can reach out to me at john@pyracantha.co.uk

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