A greenhouse in a small garden

Essential greenhouse guide

Find out all you need to know about choosing, siting and caring for a greenhouse in our essential guide.

A greenhouse is a valuable addition to any garden. It’s ideal for sowing seeds, growing tender crops like tomatoes and cucumbers and overwintering tender plants.

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You can also grow conservatory or greenhouse plants that enjoy the year-round protection that a greenhouse provides. 

There’s a lot to consider when siting and choosing a greenhouse. Read on for our advice on choosing, siting and building a greenhouse, plus keeping it functioning well – including fitting guttering, adding an automatic vent opener, cleaning, insulating and heating it in winter.

A greenhouse is a valuable addition to any garden. It's ideal for sowing seeds, growing tender crops like tomatoes and cucumbers and overwintering tender plants.

Choosing a greenhouse

There’s a lot to consider when choosing a greenhouse – including size and materials. Aluminium is cheaper and durable; wood is more expensive and holds heat well, but needs maintenance. Most people regret not getting a bigger greenhouse, so buy one as big as your budget and space allows. Read our advice on choosing a greenhouse.

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Choosing the right spot

Finding the right spot for your greenhouse is very important. You’ll need a flat spot with maximum light and sunshine, away from frost pockets and cold winds. Ideally, it should sit on an east-west axis so that it gets the most light, especially in winter. Discover the six essentials you need to consider when siting a greenhouse.

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Building a greenhouse

Building a greenhouse yourself can save hundreds of pounds – and the bigger the structure, the more you’ll save. On top of building costs, you can also save on ground levelling, building foundations and laying paths inside. If you fancy giving it a go, read our advice on building a greenhouse.

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Ventilating the greenhouse

Ventilation is a must during the summer months in particular. An automatic vent opener means your greenhouse ventilation is constantly regulated, whether you’re at home or not, and if yours doesn’t already have one, they are quick and easy to install. Find out how to install an automatic vent opener.

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Fitting guttering

Fitting guttering and installing a water butt to catch the rain not only saves water, it means that you can easily fill your watering can for your thirsty crops in summer. Plastic guttering kits are available from any DIY store. Read our guide to fitting guttering to a greenhouse.

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Damping down

Damping down the greenhouse – pouring water onto the greenhouse floor – is an important job in summer. It creates enough moisture throughout the day to prevent your plants from suffering heat stress. Find out how to damp down the greenhouse.

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Cleaning the greenhouse

Keeping your greenhouse clean means the maximum light can enter (especially important in winter) and means that there is less chance of pests and diseases lurking. Clean in spring and autumn, before and after the main growing season. Alan Titchmarsh gives advice on how to clean your greenhouse in this No Fuss guide.

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Heating the greenhouse

Insulating your greenhouse with a layer of bubble wrap will give your plants a helping hand through winter, while still letting in light. If you’re overwintering plants, a max/min thermometer and a greenhouse heater can be useful. Read our advice on how to keep the heat in your greenhouse in winter.

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Essential kit

Greenhouse staging raises plants off the ground, avoiding cooler air, and gives a convenient height for working. Slats increase air circulation, reducing fungal problems. Propagators help to ensure success with seed sowing; a heated propagator or mat will speed up germination and rooting. Read more about essential greenhouse kit.

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Greenhouse alternatives

  • A polytunnel is cheaper but less attractive than a greenhouse but a good way of growing summer crops such as tomatoes, and winter crops such as lettuce. Polytunnels are expensive to heat over winter and don’t give enough protection to be used for overwintering tender plants. Find out how to build a polytunnel.
  • A cold frame is the traditional way of supplementing a greenhouse. It can be used for hardening off plants, taking cuttings and shielding plants from the worst of the winter weather. It can also be used for sowing seeds that need cool conditions and gives good protection for winter lettuces and salads. Read our step-by-step guide to making a cold frame.
  • Mini greenhouses are useful in small gardens. They can be used to raise seedlings or grow crops such as aubergines, peppers and tomatoes.