Cucumbers are the perfect summer vegetable, adding a crisp fresh taste to salads and summer drinks. It’s easy to grow your own cucumbers, and growing them yourself always seems to make them taste better. Choose from indoor or outdoor cucumber varieties, depending on whether or not you have a greenhouse.
How to grow cucumbers
Sow cucumber seeds into pots of peat-free, multi-purpose compost in spring. Keep them in a warm spot – at least 20ºC, to aid successful germination. Pot seedlings on after they have developed their first pair of ‘true’ leaves. If growing outdoor cucumbers, harden off plants by gently acclimatising them to outdoor conditions, after all risk of frost has passed. Tie them into a sturdy support, such as a bamboo cane, and water regularly. When your cucumbers start to flower, feed weekly with a high potash fertiliser, such as a liquid tomato food. Keep an eye out for powdery mildew on the leaves, as well as cucumber mosaic virus, and harvest cucumbers as and when they are ready.
More on growing cucumbers:
Follow our detailed Grow guide to sowing, growing and harvesting cucumbers, below.
Sowing cucumber seeds
How to grow cucumbers – sowing cucumber seeds
Fill small 5cm pots with peat-free, multi-purpose compost and sow two cucumber seeds per pot and water. The seeds need heat to germinate – at least 20°C – so place pots in a greenhouse, heated propagator or on a sunny windowsill for the best results.
How to care for cucumbers
Misting cucumbers in a greenhouse
Cucumbers need plenty of heat an humidity, so are best grown in a greenhouse. Outdoor cucumbers still need very warm conditions – don’t even think about planting cucumbers outdoors until June.
Plant seedlings out when they have two or three leaves. Water cucumber plants regularly and mulch the soil to retain moisture and keep the area around them weed-free. Increase humidity by spraying the cucumber plants with a fine mist from your hose. You could even section off an area of your greenhouse, using Bubblewrap, to further aid humidity.
All cucumbers need support for their trailing stems. Trellis, bamboo canes or netting work well and you can tie the stems in if necessary. Water regularly and feed weekly with a high potash feed, such as a liquid tomato feed, when plants start flowering.
Cucumbers bear male and female flowers. You can tell them apart as female flowers have an immature fruit behind it. Some F1 varieties, such as cucumber ‘Bella’ bear only female flowers. However, if your cucumber plants produce male flowers, remove these as pollination can make the fruits taste bitter and be full of seed.
How to harvest cucumbers
Harvesting a small cucumber
Cucumbers on outdoor plants will be ready from midsummer to early autumn. Indoor cucumbers will be ready sooner. The more cucumbers you pick, the more the plant will produce. Some longer cucumber varieties can be cut in half while still on the plant and left to form a callus, so they can be used later.
Watch Monty Don explain how to harvest cucumbers by cutting them in half:
How to store cucumbers
How to grow cucumbers – pickling cucumbers
Cucumbers are generally best picked fresh and eaten immediately. They can be stored for a few days in the fridge. Smaller cucumbers can be pickled.
Great cucumber recipes
See some of the great cucumber recipes from our friends at Olive Magazine.
Growing cucumbers: problem solving
How to grow cucumbers – cucumber foliage with powdery mildew
Cucumber mosaic virus is spread by aphids. It’s easily spotted as the leaves develop a distinctive yellow mosaic pattern. This disease will stunt the growth of your cucumber plants and affect flowering and fruiting. There’s no treatment, so the only course of action if you find signs of the disease, is to destroy any infected plants. You should also avoid touching other plants to stop the disease spreading.
Powdery mildew can appear on leaves as white powdery patches. These cause the leaves to become stunted and shrivel. It’s often caused by under-watering, although there are cultivars available that are more resistant.
Whitefly can prey on greenhouse-grown cucumbers. These tiny white insects affect the plants by sucking sap. The honeydew they produce causes the growth of black, sooty mould, affecting the healthy growth of the plant.
Red spider mite can affect greenhouse cucumbers in warmer weather. The treatment is to burn the affected leaves which look rusty. Biological controls are also available.
Protect young seedlings against slugs and snails.
Cucumber varieties to try
- ‘Burpless Tasty Green’ – this popular, easy-to-grow ridged cucumber can be grown indoors or outside. Produces 25cm cucumbers with very high vitamin levels
- ‘Bella’ – an all-female flower variety, producing long 35cm fruits. It can be grown in an unheated greenhouse and has a good tolerance to powdery mildew
- ‘F1 Delistar’ – a new and unusual variety for the greenhouse, with thin, translucent skin, so no need to peel
- ‘Mini Munch’ RHS AGM – this all-female flower variety produces very small but tasty 7cm fruits
‘Petita’ – an all-female flowering variety producing lots of small cucumbers, this is one for the greenhouse