Grow your own: Cucumbers

Mar 3, 2023

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The traditional long, smooth cucumbers need to be grown in awarm, almost hot, humid atmosphere so require greenhouse or polytunnel conditions.

Some of the smaller-fruited more prickly varieties can be grown outside on your veg plot. Many of the greenhouse varieties sold are now all-female plants which means there is no need to remove the male flowers.

The ordinary old-fashioned varieties produced male and female flowers on the same plant and if the female flowers were pollinated by pollen from the male flowers then the subsequent fruit was often bitter. Some of the outdoor types still produce male and female flowers, but don’t need the male flowers removing.

Cucumber varieties

Carmen F1’
An all-female variety that has an RHS Award of Garden Merit. It also has good disease resistance and fruits are produced in profusion.
‘Cupino’
Another all-female variety that produces very small cucumbers. It is best in a greenhouse but can be grown outside.
‘Long White’
A pure white form that can be grown outside. It has a thin skin and so peeling is not necessary. Don’t remove any of its male flowers.
‘Swing’
A new variety that is good for in or outdoor production. The fruits are slightly prickly and about 20cm (8in) long.

Sowing & growing cucumbers

Sow seeds in small individual 9cm (31⁄2in) pots or in cell trays in multipurpose compost about 13mm (1⁄2in) deep. Water well and place in a propagator at 24C (75F).

Cucumbers need good warm conditions to germinate. Once the seedlings are through reduce the temperature slightly and place in a well-lit spot to grow on.

If sowing in February grow on indoors at no lower than 15C (60F). If you want to grow on in a greenhouse at this time of year, some heat will be required.

If you want to sow and grow on in an unheated greenhouse then wait until April to sow. The plants may need potting on into 13cm (5in) pots once they outgrow their small pots. Keep in warm conditions at this stage to encourage new growth.

Growing on cucumbers

By about May the plants will be ready for planting into the greenhouse, either into the borders or preferably into a special raised bed filled with layers of manure and sterilised soil or compost. The modern way is to grow in growing-bags. The compost is rich and perfect for cucumbers.

The problem with growing direct in your greenhouse border soil is the build-up of disease. Outdoor varieties can be planted out in June and the soil is best earthed up in mounds with plenty of farmyard manure or garden compost incorporated.

The outdoor ones are usually best left to trail along the ground but the greenhouse cucumbers are tied to wires or canes erected in the greenhouse. Use soft string to tie up the stems on a regular basis to keep them well supported.

Feed the plants weekly with a high nitrogen feed, such as dried blood or a general-purpose feed such as Westland Feed-All or Miracle-Gro. Once the growing tip of the plant has reached the greenhouse roof, remove it.

The side shoots growing off the main stem will bear the female flowers. These can also be ‘stopped’ (growing tip removed) about two leaves beyond a female flower. This will encourage all the plant’s energy to go into swelling the fruit.

Keep the greenhouse well ventilated on hot sunny days and dampen down the floor regularly as cucumbers love a humid atmosphere.