Cucumber will do best under cover, ideally in a greenhouse or polytunnel to keep the plants warm right through the summer months. If you don’t have access to a greenhouse/polytunnel, you can grow them outside. Here are a few golden rules to grow by:
Plant in a site that gives maximum warmth, sun & shelter
If you can find a spot next to a south-facing brick or stone wall that will reflect heat back and keep them a bit warmer during the nights, this will be ideal. Pots are brilliant for cucumbers as you can move them around a bit, and make good use of the best spots in your garden.
Don’t plant out until the nights are warm!
If you are planting them outside, please don’t plant them out until the temperatures are warmer at night and ALL risk of frost is well passed – it is best to grow them in pots on a windowsill or in a porch until then.
Give them a cloche while they are small
While the seedlings are young and relatively unestablished, we’d recommend covering them with a cloche. This will help them find a little warmth while they get going. You can happily cut a plastic lemonade bottle in half, and use that as a mini cloche.
Give them rich soil and keep them well watered
Cucumber plants will thrive best in rich soil, and this is all the more important when growing outside as it will help to keep them strong – add plenty of compost when you plant them, and a handful of wormcast fertiliser will really help. You can give them a liquid feed or wormcast tea fortnightly once they start fruiting. Try to keep the soil consistently moist but not waterlogged.
Pinch out to focus their energy on fruits
If growing up a trellis, we would normally advise pinching off the growing tips when they reach head-height. However, if growing outside, it can be beneficial to pinch out a little earlier to force the plants to put their energy into fruit production rather than foliage/vine growth.