How to Grow Cucumbers: My Guide to Growing Proper Cucumbers

I want to teach you how to grow cucumbers because not only is it relatively simple but shop-bought varieties of cucumbers have been bred for shelf life and uniform appearance, not flavour. When I harvested my first ridge cucumber from a plant growing against my south-facing fence, the difference was remarkable. The crisp texture and fresh taste bore little resemblance to what I’d been buying. Cucumbers can seem temperamental, but once you understand what they need, they’re actually quite generous producers.

The key thing to know is that cucumbers aren’t a single crop. We’ve got greenhouse cucumbers, which are smooth-skinned and need warmth, and outdoor or ridge cucumbers, which are shorter with bumpy skin and much more forgiving of British weather. Then there are gherkin varieties if you’re after pickling cucumbers. Each type needs slightly different treatment, though the basic principles remain similar. I’ve grown all three types over the years, and whilst greenhouse cucumbers certainly crop more heavily, I’ve found outdoor varieties far more reliable for beginners.

This guide will walk you through everything I’ve learned about growing cucumbers successfully in our unpredictable climate. Whether you’ve got a greenhouse, polytunnel, or just a sunny corner of the garden, you can grow brilliant cucumbers with the right approach. For more on this, see our guide on the complete guide to growing perfect courgettes.

What You’ll Need

Getting your materials sorted before you start makes the whole process smoother. I’ve learned through trial and error that having everything to hand saves a lot of rushing around later.

Seeds and Plants

You’ll need to decide between starting from seed or buying young plants. Seeds give you much more variety to choose from and work out cheaper if you’re growing several plants. Look for varieties suited to your growing conditions. For greenhouse growing, try ‘Carmen’ or ‘Bella’, both all-female varieties that won’t need pollinating. For outdoor growing, ‘Marketmore’ and ‘Burpless Tasty Green’ have served me well. Gherkin varieties like ‘Venlo Pickling’ are brilliant if you want smaller fruits.

Young plants from garden centres cost more but give you a head start of about six weeks. They’re particularly useful if you’ve missed the seed-sowing window or if you only want one or two plants. You might also find from wilting to flourishing: my parsley growing journey helpful.

Growing Medium and Containers

Cucumbers are hungry, thirsty plants that need rich soil or compost. I use a mix of garden compost and well-rotted manure for outdoor plants, whilst greenhouse cucumbers go into large pots filled with multipurpose compost with added organic matter. Each plant needs at least 30 litres of growing medium, so proper buckets or large pots work well.

You’ll also need supports. Greenhouse varieties climb readily and need sturdy canes or strings reaching up to 1.8 metres. Outdoor types can sprawl on the ground, but I prefer training them up supports to save space and keep fruits clean.

Additional Equipment

A watering can with a rose attachment helps deliver water gently without washing away compost. You’ll want liquid feed too, something tomato feed works brilliantly once plants start flowering. Fleece or cloches protect outdoor plants during cold snaps. Garden twine, soft ties, and bamboo canes complete the basic kit. If you’re growing in a greenhouse, a small fan improves air circulation and helps prevent mildew.

Step-by-Step Instructions

Starting Seeds Indoors

I start cucumber seeds indoors from mid-April onwards. Any earlier and seedlings get leggy waiting for warm enough conditions outside. Sow seeds on their edge about 2cm deep in small pots, two seeds per pot. Cucumber seeds need warmth to germinate, ideally 20-25°C, so a heated propagator helps enormously. Without one, a sunny windowsill or airing cupboard works, but germination takes longer.

Seedlings usually appear within a week. Once they’ve developed their first true leaves (the ones that look like cucumber leaves, not the initial round seed leaves), remove the weaker seedling from each pot. Keep them somewhere bright and warm. I pot them on into larger containers once roots start showing at the drainage holes, usually after two or three weeks.

Preparing the Growing Site

Cucumbers need warmth, shelter, and rich soil. For outdoor plants, choose the sunniest spot you’ve got, ideally south-facing and protected from wind. I dig in plenty of compost or well-rotted manure a few weeks before planting, about a bucketful per square metre. The soil needs to drain well whilst holding moisture, which sounds contradictory but that’s what organic matter achieves.

In greenhouses, prepare large pots or growing bags in a position where plants can climb. I prefer pots as they dry out less quickly than growing bags. If you’re planting multiple cucumbers, space them at least 45cm apart. They spread considerably and need good air flow to prevent fungal problems.

Planting Out

This is where patience matters. Cucumbers absolutely despise cold, and one chilly night can set them back weeks. I don’t plant outdoor cucumbers until late May or early June, when all frost risk has passed and soil has warmed up. Greenhouse plants can go in from late April if you’ve got heating, or mid-May without.

Harden off indoor-raised plants gradually over ten days, taking them outside during the day and bringing them in at night. When planting, keep the stem base slightly proud of the soil surface to prevent stem rot. Water thoroughly after planting and consider putting cloches over outdoor plants for the first fortnight to give them a warm start.

Training and Supporting Plants

Greenhouse cucumbers need training up vertical supports. I pinch out the growing tip once plants reach the greenhouse roof, which encourages side shoots. These side shoots produce the flowers and fruits. Pinch side shoots back to two leaves beyond each developing fruit. It sounds fussy, but this training concentrates the plant’s energy into producing cucumbers rather than excessive foliage.

Outdoor varieties need less precise training. I let the main stem grow up a support and allow side shoots to develop naturally. Some gardeners let them sprawl, but vertical growing keeps fruits cleaner and easier to spot. Ridge cucumbers benefit from having their main growing tip pinched out after six or seven leaves to encourage bushier growth.

Watering and Feeding

This is where most cucumber problems start. These plants need consistent moisture, never bone dry but never waterlogged. I water little and often rather than occasional heavy soakings. In hot weather, greenhouse cucumbers might need watering twice daily. The compost should feel like a wrung-out sponge.

Start feeding once the first fruits begin swelling. I use a high-potash liquid feed, the same stuff you’d give tomatoes, every week or ten days. Irregular watering causes bitter-tasting fruits and odd shapes, whilst overfeeding produces lots of leaves but fewer cucumbers. Getting this balance right takes a season or two of practice.

Pollination Matters

Modern greenhouse cucumber varieties are all-female, producing fruits without pollination. If they do get pollinated, fruits turn bitter and swollen at one end. Keep greenhouse doors closed when outdoor cucumbers are flowering to prevent insect pollination, or grow only all-female varieties.

Outdoor cucumbers need pollinating by insects. If pollination is poor, you’ll see tiny fruits that yellow and drop off. Hand-pollinating helps on cold days when insects aren’t active. Pick a male flower (the one without a tiny cucumber behind it), remove the petals, and brush the centre against female flowers.

Harvesting Your Cucumbers

Start harvesting when fruits reach a usable size, which varies by variety. Greenhouse types are usually ready at 30-40cm long, whilst outdoor varieties are shorter and stubbier. Don’t wait for them to get enormous as this exhausts the plant. I harvest regularly, which encourages more fruits to develop.

Cut fruits with a sharp knife rather than pulling, as tugging damages stems. Check plants every two or three days during peak season as cucumbers grow surprisingly quickly. A well-fed plant in good conditions can produce 25 or more fruits over the season.

Common Mistakes to Avoid

Planting Too Early

I’ve watched countless gardeners lose plants to cold weather because they were too eager. Cucumbers are tropical plants that simply won’t tolerate British spring temperatures. Even if cold doesn’t kill them outright, it sets them back so badly that they never recover properly. Plants that go out in June often catch up with those planted in early May.

The same applies to seed sowing. Seeds started in March spend too long indoors, becoming stretched and weak. Late-sown seeds that go straight out when conditions are right always perform better.

Inconsistent Watering

Cucumbers that experience drought stress produce bitter, misshapen fruits. When plants wilt and then get a heavy watering, fruits split. I learned this the hard way during a hot spell when I went away for a few days. The cucumbers that developed afterwards were so bitter they were inedible.

Mulching around outdoor plants helps maintain even moisture. In greenhouses, adding water-retaining granules to compost when potting up reduces how often you need to water, though don’t rely on this completely. Setting up an automatic watering system makes life much easier if you’ve got several plants.

Overcrowding Plants

Cucumbers need space and airflow. Cramming multiple plants into a small greenhouse might seem efficient, but it creates perfect conditions for powdery mildew and other fungal diseases. I space greenhouse varieties at least 45cm apart and thin outdoor plants similarly.

Poor air circulation also reduces pollination in outdoor types and prevents foliage drying quickly after watering, which increases disease risk. Sometimes fewer, well-spaced plants actually produce more than a crowded patch.

Ignoring Variety Selection

This trips up many beginners. Greenhouse varieties planted outdoors struggle with our weather and produce poorly. Outdoor varieties grown under glass become sprawling monsters that take over the entire space. Match your variety to your conditions. I keep both types going, greenhouse cucumbers for early heavy crops and outdoor ones for late summer when greenhouse space is needed for tomatoes.

Expert Tips

Succession Sowing for Continuous Crops

Rather than starting all plants at once, I sow seeds every three weeks from mid-April through early June. This gives a succession of plants coming into production, extending the harvest season right through until October if weather cooperates. It also provides insurance against losing plants to pests or disease.

The later sowings often escape cucumber beetle and aphid problems that affect early plants. They also mature during warmer weather, growing more vigorously with less coddling.

Companion Planting Benefits

I’ve found that nasturtiums planted near outdoor cucumbers attract aphids away from the crop. They’re a sacrificial plant that takes the hit whilst cucumbers grow unmolested. Radishes sown between cucumber plants mature quickly before the cucumbers spread, making efficient use of space.

Avoid planting cucumbers near potatoes, as both can suffer from similar fungal issues and one can infect the other. Strong-smelling herbs like sage and rosemary may deter some pests, though I’ve found physical barriers more reliable.

Dealing With Powdery Mildew

This whitish coating on leaves is almost inevitable on outdoor cucumbers by late summer, particularly during humid weather. I’ve found that removing affected leaves promptly, ensuring good airflow, and watering the soil rather than leaves all help slow its spread. Some varieties show better resistance than others.

Whilst various folk remedies exist, good cultural practices work better than sprays. Keep plants well-fed and watered, as stressed plants succumb faster. Once mildew really takes hold, there’s little to be done except harvest remaining fruits and remove plants.

Using Shade Cloth in Hot Summers

During particularly hot spells, greenhouse cucumbers can suffer from excessive heat, even with all vents and doors open. I’ve had success using 30% shade cloth over the greenhouse roof during heat waves, which drops temperatures enough to prevent stress without reducing light levels too much. Outdoor plants in very exposed positions also benefit from temporary shade during extreme weather.

Saving Space With Vertical Growing

Even outdoor varieties can be trained vertically up wigwams or trellises. This approach works brilliantly in smaller gardens where ground space is precious. I use sturdy supports as cucumber plants get heavy once laden with fruit. Training them up rather than along also makes harvesting easier and keeps fruits cleaner.

In raised beds, positioning supports at the north end prevents shading other crops. The vertical structure also improves airflow around plants, reducing disease pressure.

Frequently Asked Questions

Can I grow cucumbers in pots on a patio?

Absolutely, and I’ve had excellent results with this approach. Use large containers, at least 30 litres capacity, filled with good quality compost enriched with organic matter. Both bush varieties and compact climbers work well. The key is positioning pots in full sun and maintaining consistent watering, as containers dry out quickly. You’ll need to feed more frequently than with ground-grown plants, about once a week once flowering starts. Choose a sheltered spot as wind can damage leaves and dry out compost rapidly. Compact varieties like ‘Bush Champion’ are specifically bred for container growing.

Why are my cucumbers bitter?

Bitter cucumbers usually result from stress, particularly irregular watering. When plants experience drought followed by heavy watering, they produce cucurbitacin, the compound that causes bitterness. Extreme temperatures, either very hot or unexpectedly cold, trigger the same response. Old, overripe fruits also turn bitter. Some older varieties are naturally more prone to bitterness than modern cultivars. In greenhouse types, accidental pollination causes bitter fruits. The bitterness often concentrates in the skin and stem end, so peeling and cutting off the ends sometimes salvages mildly bitter cucumbers, though prevention through consistent care works better.

How often should I harvest cucumbers?

Check plants every two to three days during peak season. Cucumbers grow remarkably quickly, particularly in warm weather, and can go from perfect size to overgrown in less than a week. Regular harvesting encourages plants to produce more fruits. If you leave mature cucumbers on the vine, the plant thinks its job is done and stops producing new ones. Even if you can’t use all the cucumbers immediately, harvest them when ready and give extras to neighbours or preserve them. I’ve found that keeping on top of harvesting extends the productive season by several weeks compared to leaving fruits to mature fully before picking.

Do cucumbers need a greenhouse or can they grow outdoors?

Both options work, but you need the right varieties for each. Greenhouse cucumbers produce longer, smoother fruits and heavier crops, but they need protection from our weather. Outdoor or ridge cucumbers are shorter with bumpy skin, but they’re much more forgiving and actually taste excellent. I grow both types, starting greenhouse ones early for summer crops and outdoor ones for late summer and autumn. If you only have outdoor space, ridge cucumbers will do well in a sunny, sheltered spot, particularly trained up supports. The south of England and sheltered urban areas offer better conditions for outdoor cucumbers than exposed northern or coastal locations.

What’s eating holes in my cucumber leaves?

Several culprits cause this problem. Slugs and snails are the most common, particularly attacking young plants. Check at night with a torch when they’re active. Cucumber beetles, small yellow-green insects, can also damage leaves, though they’re less common here than in other countries. Caterpillars occasionally munch leaves, leaving ragged holes and droppings. For slugs, I use copper tape around pots or beer traps nearby. Hand-picking caterpillars works for small infestations. Once plants are established and growing vigorously, they usually outgrow minor damage. If large sections of leaves are disappearing overnight, suspect slugs. Smaller, neater holes might indicate beetles or caterpillars.

When is it too late to plant cucumber seeds?

The latest I’d sow seeds is mid-June. Plants from these sowings start cropping in August and continue into October if weather stays mild. Later sowings don’t have enough warm weather left to mature properly. That said, buying young plants from garden centres extends the planting window into early July. These establish quickly and can still produce worthwhile crops. The timing depends somewhat on your location. In milder southern and western areas, late plantings fare better than in colder northern regions. Greenhouse cucumbers have a longer useful season than outdoor types, as you can maintain warmer conditions into autumn.

Should I remove male flowers from cucumber plants?

It depends on what you’re growing. Modern greenhouse varieties are all-female and produce no male flowers, so there’s nothing to remove. If you’re growing older greenhouse varieties that produce both male and female flowers, yes, remove males to prevent pollination, which causes bitter, swollen fruits. You can identify male flowers as they have thin stems, whilst female flowers have a tiny cucumber behind them. Outdoor ridge cucumbers need their male flowers left in place because they require pollination to set fruit. Removing males from outdoor types means no crop at all. Check your seed packet, as it usually specifies whether the variety needs pollinating.

Conclusion

Growing cucumbers successfully comes down to understanding their needs and matching varieties to your conditions. They’re warm-season crops that need consistent care, particularly with watering, but the reward is fresh cucumbers that taste completely different from shop-bought ones. Start with outdoor ridge varieties if you’re new to growing them, as they’re more forgiving of the inevitable mistakes we all make.

The techniques I’ve shared come from growing cucumbers in various situations, from tiny urban greenhouses to larger kitchen gardens. What works brilliantly one season might need adjusting the next, depending on weather. Keep notes on what you grow, when you planted, and how plants performed. This record becomes invaluable for planning future seasons.

Don’t be discouraged if your first attempt doesn’t produce armfuls of perfect cucumbers. Even experienced growers have seasons where plants struggle. Learn from what goes wrong, adjust your approach, and try again. The satisfaction of picking sun-warmed cucumbers from your own plants makes the effort worthwhile.

Author: Megan Walker

Megan focuses on seasonal food, kitchen garden growing, and how households can reconnect with where their food comes from. Her writing blends practical growing advice with ideas for cooking and eating in season. With a passion for fresh ingredients and sustainable living, Megan’s articles help readers make the most of local produce while supporting British farms.