Modern ‘all female hybrid’ cucumbers provide such an abundance of fruit that a gardener needs only one or two plants to feed a whole family. May is the ideal time to start growing your own crops either from seed in the greenhouse or in pots ready to plant out - just remember to harvest your cucumbers regularly, while they are at their very best, and you’ll be tucking into fresh and tasty fruits all summer long.
Cucumbers (Cucumis sativus) belong to the family Curcubitaceae which includes courgettes, melons, marrows, pumpkins, winter squashes and gourds. The identical looking 30-40cm, smooth or very slightly ribbed, dark green-skinned cucumbers that are wrapped in polythene film and sold in the supermarket all year round are the reason many gardeners assume that cucumbers have to be straight and green. However, many of the ‘all female’ varieties that made these crops possible did not appear until 1969 with ‘Pepinex 69’, ‘Uniflora’, ‘Femspot’ and ‘Rocket’ introduced in quick succession.
These have since been superseded with modern varieties such as ‘Carmen’, ‘Bella’, ‘Flamingo’ and ‘Euphya’ which all have increased resistance to mildew and other fungal diseases, plus better fruit quality even when raised in less than ideal growing conditions. Gardeners can now also grow ‘half-sized’ fruits of 20cm length such as ‘Petita’ which led the way in the early 1980’s, and ‘Passandra’ which was developed slightly later on.
More recent breeding has focused on ‘snack-box’ or ‘bite sized’ fruits which are harvested and eaten before they are no longer than 8cm, making them ideal for children’s lunchboxes and boosting our daily veg intake. Popular varieties include ‘Cucino’, ‘Rocky’ and one of my own favourites, ‘Mini Munch’ that yields huge numbers of small crisp fruits.
Outdoor varieties were traditionally called ‘ridge cucumbers’ as they were planted on a ridge of soil. ‘Marketmore’, ‘Burpless Tasty Green’, ‘Green Fingers’ and ‘Vega’ are all popular varieties, as are gherkin crops such as ‘Diamant’, plus the round ‘Crystal Apple’ which produces pale, creamy-green, golf ball sized fruits. However it is important to note that these are all ‘mixed flower’ varieties and that removing any male flowers from the plants will result in no fruits being formed.
‘All female’ varieties can be very expensive to buy from seed so a heated propagator is a worthwhile investment, allowing you to create the perfect conditions for seed germination. Sow seeds individually, 15mm deep, into 7cm pots of moist seed compost and set the temperature to 21°C. Once seedlings have started to emerge this can then be reduced slightly (but do not allow the temperature to go below 15°C). Transplant young crops to 13cm pots as soon as the first leaves develop, then move greenhouse varieties into larger containers or growing bags once they are a little more established. Just like tomatoes, greenhouse cucumbers will need support ideally from an overhead wire fixed horizontally above head height to the structure of the greenhouse. You’ll also want to remove all forming fruits 45cm from the base of the plant so that none touch the soil. This will help your plants to grow strongly and increase yields.
Greenhouse (and indeed all cucumber) varieties will benefit from a high-nitrogen feed early on, and then a weekly potash mix of tomato and potato feed while fruiting. Keep the greenhouse well ventilated to avoid leaf mould (Cladosporium) and watch out for red spider mite which can be problematic during very hot and dry conditions, either by dampening down the floor or using biological controls.
Cucumbers that are destined for outdoors can be planted out once frost risk and biting winds have passed. Choose a sunny position and space your plants at least 90cm apart in each direction to allow plenty of room for cropping. They’ll be happiest in rich, moist soil, so don’t forget to mulch your cucumbers well during hot, dry weather and water them regularly.
Harvest cucmbers before any yellowing begins with a sharp knife or secateurs to ensure a clean cut and avoid any disease infection (you can also remove old or damaged stems in the same way). Cut crops regularly to ensure optimum fruit quality and flavour.