How to Grow Cucumber in the Greenhouse

Summer would not be the same without cucumber for sandwiches and salads. If you have a greenhouse, cucumbers are fairly easy to grow, and a couple of plants will reward you with a constant supply of fresh fruits. If you have a sunny, sheltered spot on the patio, some greenhouse varieties are worth trying outdoors, too.

You can grow cucumbers from seed, but ready-grown plants are widely available in garden centres and are easier to look after if you do not heat your greenhouse earlier in the spring.



If you start to heat your greenhouse through the spring, sow the seed in March, otherwise wait until April.


Sow the seed now if you do not heat your greenhouse. Sow seed singly in 7-cm pots containing good multipurpose compost. Seed of the all-female hybrid varieties is very expensive, so use enough to raise a couple of plants and store the surplus seed for next year.

You will need a heated propagator to maintain a minimum temperature of 25°C, and somewhere warm to grow the young plants on. Cucumber seeds should germinate in about three days under ideal conditions. You can germinate them in an airing cupboard, but transfer them to a warm, well-lit windowsill as soon as the seedlings emerge. Pot them on into a larger pot (12cm is ideal), as soon as the first leaves have fully opened. This avoids disturbing the roots by potting on several times.


About four weeks later, when the young plants have four or five leaves, they should be ready to plant out. But wait until early June if the greenhouse is unheated. Harden them off carefully if you have raised them indoors.

Do not buy cucumber plants too early, unless you have somewhere warm to keep them. Cucumbers are vulnerable to soil rots, so it is best to grow them in growing bags or pots filled with multipurpose compost. Plant two plants to a standard growing bag, or one plant to a 15-litre pot. If you choose to grow them in the greenhouse border, change the position each year, alternating with tomatoes to prevent diseases building up.


Plant out in an unheated greenhouse in colder areas. Keep watering to a minimum water only in the morning to avoid wet soil overnight. It is easy to overwater cucumber plants at this stage. Cut slits in the growing bags near the base to drain off excess water.

Cucumbers prefer a temperature of at least 21°C. If you have automatic greenhouse vent openers, set them to this temperature. Start training the plants.


As the plants grow, gradually increase the watering. If possible, use water at greenhouse temperature, rather than straight from the tap. To save time make a mini-reservoir for each plant out of a plastic drink bottle. Cut off the base and make a small hole in the cap. Push the bottle cap-end first into the compost and fill with water. The water will seep out over a couple of hours.

Growing bag compost should contain sufficient nutrients for about four weeks. Once the first fruits start to form, feed regularly with a tomato feed. Pick off dead or yellowing leaves from the base of the plant. Keep an eye open for pests or diseases.

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About the Author: Greenery always attracts Arthur Kunkle. He has a big garden where he plants many fruits and vegetables. His passion for gardening motivates him to write and share different tips on gardening.

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