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How to grow cucumbers and best varieties
Growing cucumbers is easy indoors and outside, even in pots. We trialled and tasted cucumber varieties to recommend the best ones to you
Cucumbers are relatively easy to grow, either in an unheated greenhouse or in a sunny spot outside. You can even grow some varieties in a hanging basket. There's no need to have slimy cucumbers at the back of the fridge as you can now grow snack-sized fruit that are perfect for lunchboxes.
The Which? Gardening magazine research team have grown and tasted a range of different varieties to bring you our Best Buy varieties. We also share our tips about how to grow them.
How to grow cucumbers: month by month
January
February
March
April
May
June
SOWING
SOWING/PLANTING
PLANTING
July
August
September
October
November
December
HARVESTING
HARVESTING
HARVESTING
HARVESTING
When to sow cucumber seeds
Sow cucumbers for growing in greenhouses or polytunnels from mid to late-April or up to mid-May in the North. For cucumbers for growing outdoors, sow in mid to late-May.
Use 5cm pots or large modules and sow singly into a Best Buy compost for sowing seeds. Seeds need to be at 20°C or more for germination: sow in a greenhouse, in a heated propagator or on a windowsill indoors. Pot on into a Best Buy compost for raising young plants once seedlings have their first true leaves and keep warm until they have about five leaves. Be careful not to overwater them or the plants can rot and die.
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Best cucumber varieties
Full testing results for cucumbers
Which? members can log in now to see the full results and detailed reviews of our Best Buy varieties. If you’re not a member, join Which? to get instant access.
Full-sized greenhouse cucumbers
Variety name
Overall rating
Yield
Number of fruits
Mildew resistance
Taste/texture
Quality/uniformity
'Bella' F1
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OVERALL RATING Ignores price and is based on: yield 25%, number of cucumbers 25%, taste and texture 25%, mildew resistance 15%, quality and uniformity 10%.
Snack-sized cucumbers
Variety name
Overall rating
Length of harvest (weeks)
Number of fruits per plant
Yield per plant
Ease of picking
Powdery mildew
Taste
'Beth Alpha'
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Mini cucumbers 8-12cm; half-sized 15-20cm. OVERALL RATING Ignores price and is based on: taste 30%; yield per plant 25%; number of fruits per plant 25%; resistance to powdery mildew 10%; ease of picking 5%; length of harvest 5%.
Outdoor cucumbers
Variety name
Overall rating
Size
Yield
Number per plant
Harvest period
Shape/uniformity
Disease resistance
Eating quality
'Beth Alpha'
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Yields are from one cucumber plant. OVERALL RATING Ignores price and is based on: yield per plant 30%; number of fruits per plant 30%; eating quality (flavour/texture/skin) 25%; harvest period 5%; shape/uniformity 5%, and disease resistance 5%.
Outdoor cucumbers for containers
Variety name
Overall rating
Size
Yield
Number per plant
Harvest period
Eating quality
'Bush Champion'
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Yields are from one cucumber plant in a 30-litre pot. OVERALL RATING Ignores price and is based on: yield per plant 30%; number of fruits per plant 30%; eating quality (flavour/texture/skin) 25%; harvest period 15%.
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How we test cucumbers
We grew different varieties of cucumbers and harvested fruits two to three times a week, recording the number and weight of cucumbers for each variety and rating them for quality. We also rated the varieties for ease of picking, flavour and whether they succumbed to powdery mildew.
Outdoor cucumbers can be planted in a sunny spot outside once the danger of frost has passed in late-May or early-June.
Outdoor cucumbers need very little attention. After transplanting you may want to cover plants with fleece, if there are still some cold winds. Keep the area weed free and watch for the first fruits from late-July. Once fruiting begins and if afternoon temperatures are above 22°C, you can expect five fruits or more every week, mainly in August.
New breeding has produced small cucumber plants that are suitable for growing in hanging baskets. Put one plant per 30cm basket, using a Best Buy compost for containers mixed with a Best Buy controlled-release feed. Hang up the basket in a sunny spot outdoors and let the tendrils hang down without bothering to support them. The fruit are easy to find and should be picked when they're about 10cm long.
Growing outdoor cucumbers in pots
When we grew outdoor cucumbers in containers, we found that the plants in 30-litre containers produced one and a half times more cucumbers than those in 15-litre pots, so choose a 30-litre container to maximise your harvest.
Watering and feeding
Keep well watered – cucumbers are thirsty – and feed with a liquid fertiliser, such as tomato feed if you didn’t incorporate a controlled-release feed into the compost at planting time.
Pick cucumbers before you see any decrease of dark green in the colour. Paler skin suggests seed development, with flesh becoming harder and less sweet. Regular picking encourages development of more fruits, so it's worth checking every day under cover and every two days outside.
Outdoor cucumbers usually finishing cropping in September, but indoor plants carry on until early October.
Cucumbers can become bitter on varieties that produce both male and female flowers when insects transfer pollen from the male to female flowers. Remove male flowers as soon as they appear; female flowers have a bulge like a tiny cucumber behind the flower head. Growing all-female varieties avoids this problem.
Powdery mildew
Powdery mildew is the main problem to watch out for. Remove affected leaves, don’t overcrowd plants, ensure they’re well watered and avoid wetting the leaves when you water.
Red spider mites can cause speckled and yellowing leaves; watch out for the fine webbing they produce, too. They can be controlled with a biological control, such as phytoseiulus or amblyseius. These predatory mites will feed on the pest and deal with the problem for you.