Indoors or outdoors, growing cucumbers is easy provided you take good care of the seedlings. Cucumber seeds can be expensive, but because they produce so many fruits you will probably only need to grow one plant each year. Although some varieties grow well outside in the southern half of the UK, cucumbers do much better in a polytunnel or greenhouse where they will continue to produce fruit until the end of October at least, whereas outdoor plants usually stop fruiting by the middle of September.
There are so many different types of cucumber that deciding which one to buy can be a bit overwhelming for the first-time grower. Before you choose, you need to ask yourself a couple of questions:
1) Where am I going to grow them?
If you’re growing outside, the fruits will be smaller and won’t look as good as the long, slim cucumbers you see in the supermarkets. Growing cucumbers outside is more likely to succeed the further south and west you are in the UK. Make sure you choose a variety suited for growing outdoors, and give it a sheltered and sunny spot with good drainage.
If you’re growing under cover in a greenhouse or polytunnel, you have a much wider range of varieties to choose from, including all-female F1 hybrids. (The advantage of all-female plants is that there are no male flowers to remove.) Cucumbers hate being chilled, so sheltered conditions make a huge difference to both the size of the crop, and the quality. Most important, though, is the length of the harvest: plants under cover start a month earlier than outdoors, and keep going for six weeks after their outdoor cousins have given up.
2) What kind of cucumbers to I want to grow?
Salad types, or pickling? Some cukes are really intended for eating in a salad, while others are picked very small and then pickled. The seed catalogue, or packet, should point you in the right direction as to what to expect.
If you buy an F1 variety the seeds are likely to be among the most expensive you ever buy – sometimes over £1 each. So, you really don’t want things to go wrong. When you plant your seeds, place them standing on their edge about 1.5cms deep in a biodegradable pot. Cucumbers have delicate roots that don’t like being transplanted, and if you can plant the entire pot and forget about it, so much the better. Use a light and (if possible) sterile potting compost. Once planted the seeds should be kept moist and warm, around 20C, or they may rot. Once the seedings appear, move them to a light, warm spot and keep them well watered so they don’t get held back at all.
Cucumbers are considered a delicacy by almost all the vegetable predators around. If you don’t guard your seedlings, you’ll probably find a slug finishing off the tender central growing tip – and that, as they say, is that. A stunted cucumber plant may recover enough to eventually bear fruit, but it will be very late and probably not worth the bother. If this happens there may be no option but to cheat, and buy a plant from a reputable nursery.
If you’re growing cucumbers outside, make sure to give them the warmest, sunniest and most sheltered spot you can find. F1 varieties are not generally suitable for outside growing. If you’re under cover, shelter isn’t likely to be a problem – but shade from other plants could be. Make sure they are pampered from day one – plenty of food, plenty of light – or they’ll just sulk.
Shape the soil where you are going to plant the biodegradable pots so that it makes a low mound, and make sure that none of the stems are buried. This prevents the stems from ever being waterlogged, which causes rapid – and fatal – stem rot. To be on the safe side, it’s also a good idea to protect the seedlings with bottle cloches and copper tape and do a few ‘slug patrols’ with a torch in the evenings until the plants are off to a good start.
Cucumbers are vigorous, heavy climbers and need to be trained and tied securely. While the plants put out tendrils to grab onto nearby objects, this can work against you if you allow any crowding to occur. In that case, the side shoots will rapidly hang on to each other – and once that happens, you have a lot of difficult work ahead of you! Training the plants out to the sides avoids this and encourages strong, healthy growth. It also reduces spots where the dreaded grey mould can strike. If you don’t fancy the fuss of training, you can let the side shoots trail but do limit them to five leaves for strong shoots, and two for weaker ones. Nip them out rather than using a blade, as ragged wounds heal faster than clean cuts.
Regarding mould, here’s a tip. Female flowers grow on the end of a small green spike (the future cucumber) whereas male flowers are just small buds. If the plants produce any male flowers, pinch them off as soon as you see them. If you don’t, they’ll wither and die and then turn mouldy. Grey mould spreads fast, and it will easily make the transition from the dead, wilted flower to the healthy stem beneath – and then you’ve lost the whole shoot.
Cucumbers can be harvested at any size, but don’t let them get too big. Cucumber plants are very good at hiding a fruit or two where you’ll only find it if you look very hard. If any of the cucumbers are left to mature, the plant gets the signal that it’s time to develop seeds and stops producing fruit. So keep the plants well picked, and they’ll keep on fruiting. If you see a cucumber start to swell at one end, it means that it has been pollinated and is likely to be bitter, so nip it out as soon as you notice. This can even happen occasionally with F1 all-female plants (which don’t produce male flowers at all), as pollinating insects can travel a very long way.
Cucumbers will continue to produce outside until the weather turns cold and damp in the autumn, although in a polytunnel they can be kept going until winter frosts. In a good year you can get 70+ cucumbers from a single plant, so your friends and neighbours will probably benefit too. Even if you don’t know what to do with the fruit, keep picking it – or the plant will decide it’s time to stop and you won’t get very many more.
Varieties to try: