How to Grow Cucumbers Guide

how to grow cucumbers

Cucumbers are high in vitamins and mineral acids, and they contain very few calories. Cucumbers have a lovely refreshing taste and are great as part of a salad, on a sandwich or just as a standard snack.

When you’re ready to plant out, our Quadgrow and Duogrow are perfect for cucumbers, and will keep this thirsty vegetable perfectly watered for up to 14 days, thanks to their clever SmartReservoir watering system!

Cucumber key growing facts

Signs of Germination: 3-5 days
Potting On: After first true leaves form
Plant Out: May
Harvest: July – September

Sowing cucumber seeds in a greenhouse

We recommend that you sow cucumber seeds in a propagator, such as a Heated Propagator from February to April. If you have an Unheated Propagator you can sow your seeds in April.

Alternatively, you can sow seeds on their side about 1cm (½in) deep it pots and fill them compost with 2 seeds sowed in each pot and add some water in a greenhouse.

The seeds require heat of at least 20°C which is why growing in a temperature controlled propagator is our suggested method.

Sowing cucumber seeds outside

If sowing your cucumber seeds outside, we suggest sowing them in late May or early June. Ensure you cover the soil above the seeds with some form of frost protection – we suggest using a frost fleece or cloche.

If wanting to sow them directly into warmer soil, we suggest waiting until later in the season.

how to grow cucumbers

Growing cucumbers indoors

Cucumber grown indoors in a greenhouse form smoother and longer fruits similar to ones you can find in supermarkets. Unless you are growing all-female variety, you should remove any male flowers to prevent pollination occurring. This prevents bitter tasting fruits. You can identify female flowers as they have a swelling behind each bloom.

If you are wanting to grow your cucumbers inside in a greenhouse you can plant them into beds, large containers with compost or traditional grow bags. Our suggestion is to transplant your young cucumber plants from your propagator into a self-watering planter or a hydroponic planter in late March if grown in a heated propagator or greenhouse, or in late May if grown in an unheated propagator or greenhouse.

Using something like the Quadgrow Self-Watering Planter will mean that your plants are automatically watered as it keeps the soil at the perfect moisture level meaning your cucumbers never get too dry or waterlogged. This perfect moisture means roots have better access to oxygen which fuels faster growth and bigger harvests than grow bags.

If growing in standard pots ensure you keep the compost evenly moist, and if using grow bags again ensure they are carefully watered and looked after.

Ensure you keep the humidity high when growing indoors by watering the floor, and once your cucumber has been planted out feed every 10-14 days with a plant nutrient such as Nutrigrow Plant Food.

Consider putting in place plant supports such as a support frame, vertical wires, plant roller hooks, or bamboo canes. You can then train vines up through the support and squeeze out the growing tips once they appear at the top to boost side shoots.

Growing cucumbers outdoors

If wanting to grow cucumbers outdoors we suggest planting them out in the soil once it has warmed in late spring or early summer – consider using fleece or cloches.

For the hardening off period, a cold frame can come in handy if you want to acclimatize your plants before transplanting.

Dig in up to two bucketful’s of well-rotted organic matters, such as multi-purpose compost before planting.

Outdoor cucumber varieties are called ‘ridge cucumbers’. They are often shorter, plumper and spiny or rough tot touch. These require pollination as they product both male and female flowers.

We suggest that you pinch out the growing tips when the plant has developed six leaves. This helps to produce side-shoots which can trail over the ground or up onto a vertical support, especially when the heavy fruits start to develop.

Growing cucumbers in pots

Consider growing cucumbers in pots. As cucumber plants are very ‘viney’, many gardeners shy away from planting these within their actual gardens. Growing cucumbers in pots can be a good way to conserve garden space but also doesn’t impact the yield when it comes to harvest.

Cucumbers do need plenty of water though, so ensure that your plants are well watered and have good drainage to prevent oversaturation. We also recommend planting your cucumbers in a hydroponic planter such as the Vivigrow. This Vivigrow Hydroponic Planter pumps oxygen rich water around the cucumbers roots for up to 3-4 weeks at a time

Tip: Hybrid, salad and picklebush cucumber varieties fare the best when grown in pots.

how to grow cucumbers 

Cucumbers we have grown in our greenhouse

We have grown our own cucumbers in our greenhouse no too long ago! We harvested them once they reached 20cm, and many of the ripe cucumbers measured in at 30cm!

The cucumbers reached the maximum height Gardening Angel Paul was willing to let them grow to. Therefore, he cut the growing tip out which meant that all the plants concentrated their energy on developing fruit rather than more growth. This made enough time in that season for the fruit to develop and ripen.

how to grow cucumbers

Protecting cucumbers from pests

The key pests you have to keep an eye on when growing cucumbers are the following:

1)      Slugs & snails – use slug pellets to deter them away from outdoor varieties

2)      Whitefly – these prey in cucumbers grown in greenhouses as they suck the sap which in turn causes black, mouldy growth.

3)      Mildew - is a serious problem that causes the leaves to become stunted and shrivel.

Browse our range of pest control products to ensure your cucumbers are fully protected.

cucumber plant pests 

Varieties of cucumbers to grow

Home grown cucumbers can be divided into four popular types: (1) slicing, (2) pickling, (3) burpless, and (4) space savers for small gardens and container.

Slicing: Dasher II, Greensleeves, Marketmore 76, Marketmore 80, Raider and others.

Pickling: County Fair 83, National Picking, Pickle Bush, Regal, Saladin and more.

Burpless: Burpless Hybrid, Orient Express, Sweet slice

Space Savers: Bush Champion, Bush Crop, Bush Whopper, Fanfare, Pot Luck and others.


Don’t forget that Greenhouse Sensation is still operating as normal, albeit with delivery times of up to 21 days, so if you need any fresh gardening supplies then we’re still here to help.