a 10x12 green-framed, polycarbonate greenhouse

A greenhouse is a major investment in your garden, so you’ll want to ensure it works effectively and lasts for the long-term by installing it properly.

Firstly, this means preparing a proper greenhouse base in advance of your greenhouse’s delivery.

Is A Greenhouse Base Necessary?

an orangery greenhouse on a concrete base


Yes, it’s absolutely essential.

Banish any thoughts of assembling your greenhouse directly onto soil or turf as it won’t take long for it to slip, sag and slump. The glass will likely crack, metal buckle, wood rot and door jam, leaving what should be a decades-long investment fit for nothing but the scrapheap.

The major requirement of a greenhouse base is that it is solid, level and stable. As you can build your own or buy one readymade, let’s take a look at both options.

Building A Greenhouse Base

Before building the base, you should pick a suitable position for it.

Remember that you’ll need to have sufficient room around the perimeter of the greenhouse to clean and maintain the structure. To give you an idea of the minimum space required, you should be able to get a wheelbarrow right around the outside.

Leaving this space has the added benefit of allowing air to circulate, which reduces the risk of moss and algal growth.

Once you’ve decided on the position, it’s time to build the base.

A greenhouse base has 2 parts.

First is the plinth. This raises the greenhouse a few centimetres above ground level. Next comes the actual flooring of the greenhouse. Popular options are concrete slabs or a central path of slabs with a soil border either side of it. Take your pick.

Using Slabs as a Greenhouse Base

someone laying a greenhouse base made of slabs


Make sure the soil is compacted, level and screed off with sand or pea gravel. Then you can either lay the slabs dry (not using any mortar) or wet (using blobs of mortar at the corners and one in the middle of each slab).

Be warned, slabs are thick and heavy, making them a challenge to manoeuvre, so it’s a good idea to enlist some help. On a positive note, once laid correctly, this means slabs make an excellent greenhouse base.

Remember to use a spirit level and avoid standing on the slabs until the mortar has set.

Other Types of Greenhouse Base

Bricks can also be used to create a solid base but be wary of using reclaimed materials as they may be prone to flaking and cracking over time. 

Our Readymade Plastic Greenhouse Bases

a readymade plastic greenhouse base kitIf you don’t want the hassle of laying slabs or concrete, why not buy one of our readymade plastic base kits? They keep a greenhouse level and supremely stable, as well as providing excellent ventilation, drainage and protection from ground moisture. They are also simple to reposition, if required.

These readymade greenhouse bases come in a range of sizes and consist of a heavy-duty membrane together with a strong, durable interlocking plastic grid system, which is designed to be filled with pea gravel.

Choose the appropriate size and unpack the kit. Prepare the ground where the base is to lie and ensure it is well compacted. Level out any hollows with builders’ sand or pea gravel.

Once this is done, lay the thick plastic membrane over the area to be covered by the base. Place the grids on the membrane, clipping them together to form a rigid framework. Then, spread pea gravel into each of the cells of the base. This creates a great looking finish, as well as aiding stability and drainage.

Now you can get cracking on the greenhouse itself, happy in the knowledge that you have an effective greenhouse base. 

Building Your New Greenhouse

someone using a spanner to assemble a greenhouse


We advise checking the weather forecast in advance of starting the job. Avoid assembling your greenhouse on a wet or windy day as it will be a far more difficult job.

Also, get some help. Building a greenhouse is a 2-person job.

Unpack everything, lay it out on the ground and identify all of the parts. Take time to read the instructions and make sure you have the necessary tools for the job. Once you’re confident everything is in order, it’s time to build your greenhouse.

Wear gloves and long sleeves, especially when fitting the glazing. Once the door is in position, put draught proofing around it to prevent heat from escaping, plus check that your vents are in full working order.

After Assembly

It’s a good idea to check the doors are still hanging correctly after a few weeks, just to ensure they haven’t sagged.

Heating is a great addition to any greenhouse as it extends the growing season even longer. If you choose to install an electric heater, always employ a qualified electrician. Gas and paraffin heaters both make excellent alternatives.

Now you have your new greenhouse properly assembled and functioning, you’re ready to experience the joys of greenhouse gardening.

Greenhouses for Sale

an 8x6 wooden greenhouse


If you’re still in the process of choosing your new greenhouse, you’re in exactly the right place. We stock all of the latest designs, including those with wooden and metal frames, lean-to greenhouses, and various glazing options.

View our fantastic full range of greenhouses for sale now.