How to Grow Cucumbers (Comprehensive Guide)
- Jonathan Valencia
- Oct 3
- 5 min read
Updated: Oct 7
Cucumbers (Cucumis sativus) are tender, fast-growing plants closely related to courgettes, squashes, and pumpkins. With the right warmth, moisture, and care, they produce a plentiful supply of tasty, crunchy, and refreshing fruit from mid-summer onwards.
Cucumbers really are the most refreshing snack on a hot summer day and one of my favorite plants to grow in the garden. One of the reasons I love them so much is because the harvests never go to waste. Sometimes I grow a plant that looks beautiful on Instagram, but my family just isn't interested in eating it. But even my kids agree that there's nothing better than a cucumber straight from the vine.
Let's look at the best types of cucumbers to grow at home and tips to maximize your cucumber harvest in your kitchen garden.
1. Choosing Your Variety
Cucumbers are broadly categorized by their intended growing environment:
Variety Type | Growing Environment | Characteristics & Benefits |
Greenhouse, polytunnel, large cold frame. | Longer cropping season (mid-summer to early autumn), often produce all-female flowers which must not be pollinated to avoid bitter fruit. | |
Sunny, sheltered spot outdoors. | Shorter, weather-dependent season. Produce both male and female flowers, with female flowers requiring pollination to set fruit. | |
Varies | Includes mini cucumbers (quicker harvest), gherkins (tiny fruit for pickling), and grafted plants (vigorous, larger crops, more disease resistant). |
Recommendation: Look for varieties with the RHS Award of Garden Merit (AGM), as these have performed well in trials.
Want an easy garden win? Start with cucumbers.
Cucumbers are a beginner-gardener's dream. Their seeds sprout quickly and the vines rapidly grow and climb a trellis, meaning you don't wait long for results.
Since they only require a spot in the sun, warm soil, and consistent moisture, they're truly low-maintenance. Give them this simple care, and your reward will be a bounty of fresh, crisp cucumbers, often faster than you can keep up with the harvest!
2. When and Where to Start
Cucumbers are tender plants and should be started indoors to ensure reliable germination and an earlier crop.
Sowing Indoors
Growing Location | Sowing Time |
Mid-February to Mid-March | |
Unheated Greenhouse, Polytunnel, Cold Frame | April |
Outdoors | Late April |
Sowing Process:
Fill 10cm (4in) pots with peat-free seed compost and water well.
Sow one seed per pot, 1–2cm (½–¾in) deep, ideally positioning the seed on its side.
Place in a heated propagator at 21°C (70°F) or on a warm, sunny indoor windowsill covered with a clear plastic bag.
Once seedlings appear (1-2 weeks), remove the covering/propagator and keep the young plants warm and well-lit.
Sowing Outdoors (Outdoor Varieties Only)
Sow directly into the prepared ground in late May or early June, after the soil has warmed up, in milder locations.
Sow up to three seeds per site, 1–2cm (½–¾in) deep, removing the weaker seedlings to leave one strong plant once germinated.
Cover the sowing area with cloches or plastic-free fleece to aid warmth and protect seedlings from slugs and snails.
Where to Buy Cucumber seeds
3. Preparing the Ground and Planting Out
Cucumbers need a warm, sunny, and sheltered spot with soil enriched with organic matter.
Ground Preparation (How to Grow Cucumbers)
In-Ground: Dig in two bucketfuls of homemade garden compost or well-rotted manure per site (30cm / 1ft apart) a few weeks before planting, or mulch heavily for no-dig systems.
Containers: Use pots at least 30cm (1ft) wide and deep, filled with peat-free multi-purpose compost. Standard growing bags can accommodate two plants.
Planting Times
Planting should only occur once local temperatures are reliably above 12°C (53°F).
Growing Location | Planting Time | Notes |
Heated Greenhouse | Late March | |
Unheated Greenhouse | Late May | Once temperature is consistently above 12°C (53°F) |
Outdoors | Early June Onwards | Harden off seedlings carefully beforehand to acclimatise them to outdoor conditions. |
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Planting Process: Water the plants well before planting. Position them in the centre of the prepared site or container, firm gently, and water generously. Do not disturb the rootball.
4. Providing Support
Cucumbers are climbing or scrambling plants. Growing them vertically is recommended as it saves space, keeps the fruit clean, and protects them from slugs.
Key Point: Install supports at planting time.
Growing Location | Recommended Supports |
Greenhouse | Tall, sturdy bamboo cane or vertical wire/string secured to the roof and ground. Horizontal supports may be needed for side-shoots. |
Outdoors | Wigwams, vertical stout netting on stakes, or trellis/wires attached to a wall or fence. |
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Alternative: If trailing on the ground, lay a weed-suppressing membrane underneath to keep fruit clean and prevent rotting.
5. Plant Care
Cucumbers are heavy feeders and drinkers. They require warmth and a steady supply of moisture to crop well.
Watering & Mulching
Watering: Keep the soil or compost evenly moist, especially when fruits are forming. Container/greenhouse plants may need daily watering in hot spells. Water at the base of the plant to avoid wetting the leaves, which encourages fungal diseases like powdery mildew. Use rainwater if possible.
Mulching: Apply a thick layer of garden compost or well-rotted manure around the base of the plant (leaving a gap around the stem) to retain moisture and suppress weeds.
Feeding
In-Ground: Usually not required unless soil is poor.
Containers: Feed every 10–14 days. Use a general liquid fertiliser initially, then switch to a high potash liquid feed (e.g., tomato feed) once flowering begins to encourage fruiting.
Training and Pinching Out
Pinching out restricts vigorous growth, encouraging the plant to focus energy on fruit production.
Location | Action | Purpose |
Greenhouse | Pinch out the growing point when it reaches the roof. | Restrict height. |
Greenhouse | Pinch out the tips of side-shoots two leaves beyond a female flower (has a tiny fruit behind it). | Restrict side-shoots. |
Greenhouse | Remove any rare male flowers (no tiny fruit behind them). | Prevents pollination, which can make fruits bitter. |
Outdoors | Pinch out the growing tip once the plant has developed seven leaves. | Encourage side-shoots. |
Outdoors | Pinch out the tips of flowerless side-shoots after seven leaves. | Restrict flowerless growth. |
Outdoors | DO NOT remove male flowers. | Pollination is required for outdoor varieties to set fruit. |
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Greenhouse Environment
Humidity: Raise humidity in hot weather by wetting the floor to encourage good growth and deter red spider mites and powdery mildew.
Temperature: Aim for a daytime range of 18–25°C (64–77°F). Use shading in summer to prevent the greenhouse from overheating.
6. Harvesting
Regular harvesting encourages the plant to produce more fruit.
Variety Type | Harvest Size (Approximate) | Notes |
Mini Cucumbers | 8cm (3in) long | Check every few days as they grow fast. |
Small-Fruited | 15cm (6in) long | |
Full-Sized | 20–25cm (8–10in) long |
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Harvesting Tips:
Harvest from mid-summer to mid-autumn (shorter season outdoors).
Fruits should be uniformly green, firm, and have a slightly rounded tip.
Cut the stem cleanly with a sharp knife or secateurs—do not pull the fruit.
Overripe fruits will be yellowish, bulbous, or soft.
7. Common Problems
While generally robust, cucumbers can suffer from a few issues:
Powdery Mildew: White, powdery patches on leaves, especially in low humidity. Solution: Improve air circulation, ensure steady watering (avoid wetting leaves), and increase humidity (in greenhouses). Grow mildew-resistant varieties.
Red Spider Mites: Tiny pests that thrive in hot, dry conditions (greenhouses). Solution: Maintain high humidity.
Mosaic Virus: A serious problem resulting in mottled leaves and stunted growth. Solution: Affected plants should be destroyed immediately to prevent spread.
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