Wondering how to grow cucumbers? You've come to the right place. Learning how to grow this salad staple is simple, and will reward you with a steady supply of delicious, refreshing fruits (yes, they're fruit!) for sandwiches, pickles, and more.
The most important thing when growing cucumbers is to consider which type is right for your garden: some varieties are grown indoors in a greenhouse and some are grown outdoors, so choose the most suitable one for you. Some types also do well in pots, so are perfect as small garden vegetable ideas. Cucumber seeds are usually sown between February and June and are ready to harvest from July through to October.
Keep reading for our step-by-step guide to growing cucumbers, plus more advice such as growing times, where to buy seeds, and common problems and how to avoid them.
How to grow cucumbers indoors: a step-by-step guide
Cucumbers grow well in greenhouses
- If you have a heated greenhouse, sow seeds from mid-February to mid-March. If you don't, wait until April. Sow seeds on their sides, 1cm deep.
- Move your young plants to 25cm pots in late March if you have a heated greenhouse or late May if it's unheated. Water little and often.
- You'll need to train the main stem of your cucumber plants up a wire or cane. Pinch out the tallest stem when it reaches the roof.
- You'll also need to pinch out the tips of side shoots. Where you see tiny fruits behind a flower, leave two more leaves and then pinch out. Pinch out flowerless stems at 60cm long.
- Always remove the male flowers from greenhouse cucumbers, advises Sue Sanderson at Thompson & Morgan. You can tell if they’re male because they have a plain stalk, whilst female cucumber flowers have what looks like a tiny cucumber between the bottom of the flower and the stem.
- Keep the humidity high and feed every two weeks with a balanced liquid fertiliser.
On the lookout for a new garden building to grow your crops? Take a look at our guide on how to choose a greenhouse for lots of helpful advice.
How to grow cucumbers outdoors: a step-by-step guide
No greenhouse? No problem! Some cucumber varieties can thrive when grown outdoors
- You can sow your cucumber seeds indoors in late April or wait and sow them directly outside in late May to early June. Sow the seeds 2.5cm deep and, if planting directly outside, cover with fleece or a glass jar or cloche.
- Before planting or moving outside, dig through well-rotted organic matter and a general purpose fertiliser into your raised beds or vegetable border. Try to choose a sunny but sheltered spot.
- If you started your seeds indoors, move them outdoors in early June. For best results, gradually acclimatise your plants to outdoor conditions. Do this over a course of 7-10 days, before transplanting them into the soil, as Sue Sanderson at Thompson & Morgan recommends. You can also buy young plants from garden centres and place them straight outside.
- Pinch out the growing tips when the plants have seven leaves. Sideshoots can be left to trail over the ground and pinched out when they have seven leaves if they have no flowers on.
- Outdoor cucumber varieties need both male and female flowers for pollination, so, unlike greenhouse kinds, don't remove the males.
- Keep the soil moist by watering around the plants, not directly over them.
Common problems when growing cucumbers
According to the RHS, whitefly and cucumber mosaic virus are the biggest threats to your cucumber crop. Whitefly secrete a sticky substance onto cucumbers which encourages mould to grow. Use a chemical whitefly killer outdoors or hang sticky traps in your greenhouse.
Cucumber mosaic virus causes the plants to be deformed with the leaves displaying a yellow, mosaic pattern. Destroy any infected plants and use a spray made of water and detergent to discourage aphids, which spread the virus.
Slugs can be a pain, too. Follow our advice on how to get rid of slugs in the garden to deter them from devouring your crop.
When are cucumbers ready to pick?
Pick your cucumbers with a pair of sharp secateurs
Cut full-sized fruits with a sharp knife or your best secateurs when they're about 15-20cm long. Of course, miniature versions will be ready to harvest when they're much smaller – check the label of your seeds to see how long yours will grow.
Generally, harvesting the cucumbers can be done around 12 weeks from sowing the seeds, as Sue Sanderson from Thompson & Morgan advises. Try to pick them before they show signs of producing seeds, which can make them taste bitter.
Want to try your hand at growing other crops to enjoy eating alongside your cucumbers? Head over to our guides on how to grow tomatoes and how to grow potatoes.
Where to buy cucumber seeds
Elevate your salads with home-grown cucumbers
Use our quicklinks below to buy cucumber seeds from a range of online retailers, or keep scrolling for some of our favourite varieties that you can grow in your garden this year.
Buy cucumber seeds in the UK:
- Shop cucumber seeds at Amazon
- Shop cucumber seeds at Suttons
- Shop cucumber seeds at Dobies
- Shop cucumber seeds at Thompson & Morgan
- Shop cucumber seeds at You Garden
Buy cucumber seeds in the US:
- Shop cucumber seeds at Amazon
- Shop cucumber seeds at Burpee
- Shop cucumber seeds at The Home Depot
- Shop sweet peas at Walmart
