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How to set up a greenhouse for sustainable year-round gardening

Need a guide on greenhouse gardening for newbies? Step this way! If you want homegrown produce no matter the temperature outside, a greenhouse is a smart choice.

It’s sometimes hard to know where to start. But from where to put your greenhouse, to how to best water your plants inside it, we’ve got you covered.

Location, location, location

A greenhouse works by absorbing sunlight and storing it as heat. This makes the air inside warmer than outside, extending your growing season.

Placing your greenhouse in the right spot is the key to a long growing season. So take some time working out the best spot. It will need at least six hours of sunlight each day. But also needs to be protected from high winds.

Avoid overhead trees if possible, as they’ll ‘leaf’ you in the shade during the summer. Plus you’ll have to keep removing fallen leaves.

If you live in northern England, Northern Ireland or Scotland, you set up your greenhouse against a south-facing wall to help boost temperatures.

Pro Tip: Tempting though it is to use every centimetre of space in your garden, don’t cram your greenhouse in. You’ll need to be able to access the sides and roof to clean the glass or replace panes if they become damaged.

All sizes great and small

There’s an amazing range of greenhouses on the market. The smallest look like glass cupboards. True, they won’t give you any protection from the rain. But they can squeeze into that awkward corner.

If you want a larger, more permanent structure, you’ll need a flat base on which to erect the greenhouse. Pouring a concrete slab is one option, but water can pool if you don’t get the slope angle right. Why not use paving slabs instead? They’re sturdy, water can run through the gaps and they’ll stop rodents burying up from underneath to steal your prize tomatoes!

DIY your ideal greenhouse

Want a more bespoke and sustainable option? You could consider building your own greenhouse from recycled materials. The Greenhouseinfo website has lots of ideas, from simple hoops to a geodesic design.

Pro Tip: Whether you buy or DIY, remember plants grow, but greenhouses don’t. Somewhere than can fit that lemon tree now may be pushed for space in a couple of years’ time. So do bear future growth in mind.

The Goldilocks balance

You don’t want your greenhouse to be too cold. But overheated plants won’t perform well either. Here’s the ideal temperature range:

• In summer: 24 – 30 degrees C in the day, 15 – 24 degrees C at night
• In winter: 18 – 21 degrees C in the day and 7 degrees at night

It’s only a small piece of kit, but a thermometer is vital to see if you’re getting the balance right. Use one in the first weeks of each season before investing in shade cloth or heating.

Cosy on up

No matter how sunny it is, greenhouses in the UK will need extra insulation during the winter. Rather than buying something new, think about recycling materials you already have. Insulation materials can include:

• Bubble wrap
• Foam insulation panels
• Old blankets

The smart way to heat your greenhouse

With high energy bills looking like they’re here to stay, it’s important to think about how you can sustainably heat your greenhouse during the winter months. Solar panels are one option. Air or ground source heating another. But all of these can be expensive.

A low-cost hack is to paint plastic bottles black and fill them with water. Then line them up along your greenhouse shelving where the sunlight will hit them. They’ll absorb the heat in the day, then release it through the night. Genius!

Breathing life into your plants

Plants need soil, sunshine, nutrients and water to thrive. Plus another vital resource:  air. In a garden, the wind does a pretty good job of moving air around. But in a greenhouse, it’s easy for air to stagnate. This can lead to plants rotting, or showing signs of mildew or mold.

So choose wisely when selecting your greenhouse. Rather than using electricity to power a fan, select a model with openings. An added bonus is that you can welcome in insects who can pollinate your plants!

Pro Tip: Not sure how many windows, doors or vents you need? Work out your floor space. Then divide it by 5. This figure is the area that you need to be able to open.

Thirsty work

Essentially, plants in a greenhouse need the love and attention offered to houseplants. It’s up to you to make sure they’re regularly fed and watered.

There are lots of ways to make watering your plants easier. If you install a drip irrigation system from the get-go, your future self will thank you!

Another tip is to buy a greenhouse with integrated guttering, where rain collected from the roof fills up a water butt. Or you can retrofit guttering yourself. This Gardeners’ World article on How to fit guttering on a greenhouse explains more.

Keep it clean

If you plan to use your greenhouse all year-round, you need to schedule in a thorough clean every few months. Washing panels, implements, pots, and wiping down surfaces will help to control pests and diseases. White vinegar is a great disinfectant, and is free of artificial chemicals!

Best sustainable compost for greenhouses?

In such a contained environment, it’s important not to introduce any pests. If you trust your compost heap, you can opt to DIY your compost

However if you’re at the start of your gardening journey, it will take time to create your own compost. Why not use our Coco Grow+ blend to get going? We’ve added perlite to help with drainage and keep the compost light and airy. As it’s pH neutral, it’s perfect for growing seedlings.

Coco coir comes from fast-growing coconut trees. It uses material which would otherwise go to waste. The lignins – natural good bacteria – within coco coir help with plant health. And you’re leaving valuable peat wetland habitats intact, so they continue storing carbon.

More tips from the ‘Green Gardeners Guild’ online advice library

On the lookout for more tips and hints? Our blogs are packed with advice:

• What should I grow in my greenhouse?
• Using coir for greenhouse plants
• How to grow vegetables in coco coir peat

Share your sustainable greenhouse!

If you follow our greenhouse advice, you can enjoy fresh, homegrown veggies all year long. As well as protect precious tender plants over winter. And give yourself a head start in the spring!

If you’ve set up a greenhouse for sustainable year-round gardening, congratulations! Do post your pictures and tag @cocoandcoir on Instagram. We’ll credit you for any images we use and you’ll be in with a chance to win some Coco & Coir goodies.