Cucumbers are the quintessential salad addition and once they have started cropping, you know its summer. They are very prolific plants – a single plant can produce 30-40 cucumbers so you probably won't need more than a couple of plants. I saw a tub of pickled “organic” cucumber slices (I’d say there was half a cucumber in it) in a supermarket once for €4 - a packet of cucumber seeds will cost you about €3 and will contain approx 5 seeds - that means for €3 you get 200 cucumbers - talk about value for money! And of course, nothing makes you feel like an award winning GIYer than growing an 18 inch cucumber!
Cucumbers need heat to germinate so you must sow them in pots and keep them indoors until the ground warms up. Sow from February over a heated propagation mat. Sow two seeds in a 8cm pot – place the seed on its side to prevent rotting. Sow at a depth of 2cm. Remove the weakest seedling.
Seedlings will be ready to plant out about a month after sowing but delay if weather is poor – harden them off well by bringing them outdoors each day for a few hours. You can plant cucumber plants in the polytunnel or greenhouse, or with some varieties you can sow (very successfully) outdoors. Dig a hole of about 30cm wide and 30cm deep and fill it with well rotted compost – draw the soil back over the hole to make a mound and plant the seedling in the mound. Leave a space of 45cm between plants but remember that a couple of plants should be more than enough.
Cucumber plants can be left to trail or they can be trained to grow up a cane wigwam, tied in securely (use the same support structure as you would use for tomatoes). Pinch out the growing tip of the plant once it reaches the top of the support. Cucumbers are composed mainly of water so in order for them to swell they need lots of watering – never let the soil dry out. Use a mulch on the surface if necessary. Water the soil, not the plants. You can feed them fortnightly as you would with tomatoes.
Harvest cucumbers as they ripen – if you leave them on the plant too long they will discourage the plant from producing more fruit. Keeping up with the harvest can be a problem in the summer. Cut rather than pulling from the plant.
If greenhouse cucumbers are pollinated they become bitter – all female varieties are available. In the polytunnel, cucumbers can be attacked by whitefly. Powdery mildew is a common problem as the summer progresses. Good air circulation is the main preventative measure. You can also apply a milk spray (1 part milk to 9 parts water) if you get mildew. Foot and root rot can also occur as a result of over watering. Cucumber mosaic virus is less common and characterised by yellowing skin and dark green warts – remove infected plants.