Building A Small Greenhouse

Whether for a garden or allotment, a greenhouse is a must if you want to get serious about growing plants, flowers, fruit or vegetables. It opens up a world of possibilities to the gardener and enables you to provide a suitable environment for a wide range of plants to thrive. A greenhouse can be used to protect delicate plants from winter frosts, grow exotic species in climates too cold to sustain them usually, and bring on certain plants or crops early.

Choosing your greenhouse

Greenhouses come with timber or aluminium frames. If you’re unsure what size of greenhouse to opt for, it’s recommended you choose the largest you can fit into the available space, as you’ll soon discover you quickly fill your greenhouse with plants and seedlings.


The most common glazing in greenhouses is horticultural glass. This is relatively affordable and is widely used. Another option is toughened glass – this is extremely tough compared to regular glass and is often preferred by those who have children or grandchildren who will be playing around the greenhouse. The final main option is polycarbonate. This is extremely tough and has the added advantage of diffusing the sunlight, reducing scorching of any plants inside the greenhouse.

Building A Small Greenhouse

Deciding where to site your greenhouse

It’s important you consider access to all sides of your greenhouse – so you shouldn’t site it up against a wall if possible. The greenhouse will need cleaning thoroughly at least once a year, so you should be able to access all the external glass easily. You should also avoid siting your greenhouse under the branches of a large tree. While you might think this is a good way to provide shade on the hottest days of the year, there is the risk of branches falling from the tree, in storms for example, and shattering the glass.


Most greenhouses available include air vents that you can adjust, allowing you to control the temperature and ensure a steady circulation of air. This is another reason you shouldn’t site your greenhouse right up against a building or other structure.

Building A Small Greenhouse

Interior paths

You’ll need a dry, stable surface inside your greenhouse, so think about this when you choose where to site it. Avoid areas of the garden that tend to become waterlogged or where the ground is very uneven. You’ll need to ensure the ground is level before you begin building your greenhouse, but starting with ground that is already relatively flat will make this easier. It’s easier to set out your paths before you build the greenhouse – paving slabs are a good option and provide a dry, solid surface for you to walk on. You could also consider using gravel or wood chip, if you prefer.

Gabriel Ash has a number of helpful instructional videos on the topic of building your own greenhouse, so please take a look if you need any further guidance.