How To Grow Vegetables In A Greenhouse

Fancy eating home-grown vegetables all year round? With a good greenhouse you can, and it’s nowhere near as hard as you might imagine. You’ll save money on your food bills, be feeding your family totally organic, amazing tasting, produce and will have the pride of serving up your own vegetables on the dining table.

Before you get started on your journey into the world of greenhouse veg, it’s worth getting to grips with the basics of how a greenhouse works, as well as the essential tools you’ll need to succeed in your vegetable growth.

Growing inside a greenhouse allows you, to some degree, to control the environment. Some greenhouses are more controllable than others, with high-end models allowing for temperature and humidity control, while the environment of more basic models controllable by more basic means. With this control, you are able to grow a great variety of produce, from lettuces to chilli peppers. Having said this, most vegetables are still fairly seasonal – a greenhouse simply extends the length of the season you can grow them in.

Essential Tools

In order to help control the environmental conditions of your greenhouse, and to allow you to grow great greenhouse vegetables, there are a few accessories that will help you achieve great results.

If your greenhouse is too hot, and is retaining this heat all the time, you can simply vent the air through the windows at the top of your greenhouse. Autovents detects the changes in temperature, and automatically slowly open and close the windows to allow for optimal atmospheric conditions all the time.

Greenhouse too cold? You can install a heating system, which will help to maintain a stable, warm condition in your greenhouse. If you’re feeling adventurous, you can create a heat sink, or there are all manner of other DIY contraptions that can be created to self-heat your vegetable growing extravaganza.

What Can You Grow in a Greenhouse?

The greenhouse environment is ideal – you can grow almost any kind of vegetable in it. Some vegetables require cool temperatures, whilst others are happy in hot, humid conditions. If you’re just starting out on the greenhouse vegetable growing adventure, you may be better off starting with some of the hardier vegetables, as you’ll be able to grow these without many issues, and you’ll start to feel like a green-fingered god. Once you have the basics mastered, check the conditions required for other types of vegetables, and you’ll soon have a full crop of varied veg!

Leaf Lettuce

The humble lettuce is a great starting point for greenhouse growing, although it can quickly use up a fair amount of bedding space. Varieties such as Red Sails and Black-Seeded Simpson will thrive in a greenhouse environment, and provide you with a great basis for a fresh salad. Try to maintain a temperature under 70 degrees fahrenheit.

Sowing: Mid-Spring – Short rows about 30cm apart, in a shallow trench, about 1.5cm deep.

Harvesting: 3-6 inches tall, normally after around 48 days.


Carrots prefer a cool environment, so are not very suitable for spring or summer growth in a greenhouse. Instead, grow your carrots during the winter for a harvest in early spring. Keep the conditions fairly cool for sweet carrots.

Sowing: Winter – a fairly thin spread of seeds over 1cm deep drills in the soil.

Harvesting: Most varieties can be harvested after around 10 weeks.


Spinach is a great vegetable to grow in a greenhouse. Although it can be temperamental to temperature, it will provide you with a good crop of highly nutritious leaves for very little upkeep.

Sowing: Early Autumn – about 0.5cm deep.

Harvesting:  Cut individual leaves when they are about 2cm above the ground. If you are harvesting the whole bunch, keep an eye on  the size and condition of the developed leaves.


These tasty green vegetables need a little more care when they’re grown in a greenhouse. Plant them in growing bags or in coldframes.

Sowing: Spring – 2 seeds per 2cm deep hole.

Harvesting: Mid-September – remove with sharp secateurs.


Originally from Mexico, courgettes, or zucchini, are essentially immature marrows. They need a warm environment, and should ideally be planted in grow bags. They also require a good amount of watering and feeding.

Sowing: Towards the end of April.

Harvesting: After about 12 weeks, you should be enjoying the first harvest of courgettes.

Peppers & Chillies

Conjuring up images of sun drenched hills in South America, peppers and chilli are as vibrant and enjoyable to grow as any traditional British vegetable. They grow best in a warm environment, and can require some training to achieve optimal yield. Growing these exotic vegetables tends to also work best in grow bags, with the addition of a bit of manure to encourage growth.

Sowing: Mid-February to Early April – 2 or 3 plants per grow bag.

Harvesting: From July onwards – pick green ones early to encourage further crops.