Our Organisation Search
Quick Links
Toggle: Topics



Cucumbers are available in a number of different types but the two most  commonly grown in Ireland are the glasshouse grown - slicing cucumber (English cucumber) and the outdoor grown - ridge cucumber.

There used to be a difficulty with older varieties of glasshouse-grown cucumbers in that if pollinated with seed set, the fruit became very bitter and were not pleasant to eat. To get over this problem the male flowers had to be removed by hand before pollination took place. The female flowers are identified by the swelling at the base of the flower which develops into the fruit.

Newer hybrids are now available in which the flowers are all female and so the plants will not set seed and the taste of the fruit formed will be pleasant. The fruit on these plants are smooth skinned and they will not require peeling. 

Glasshouse F1 hybrids are grown as vine plants and must be trained up a string attached to an overhead crop wire to support the plant and allows the fruit to hang down and grow straight. Outdoor ridge varieties can be allowed to trail along the ground. They produce both male and female flowers.

The female flowers must be pollinated by pollen from the male flowers for cucumbers to develop. Outdoors this will happen naturally, with the help of insects. Do not remove any flowers from ridge cucumbers. If the plants are grown under the protection of a cloche or frame these must be opened up during the day to allow insects have access to the flowers. The plants are grown on a mounded ridge to help avoid waterlogged conditions which would tend to encourage root rots. Space required per plant will be about 2.5m2.

Site and soil

Outdoors: as for tomatoes.
Greenhouse: as tomatoes in border soil or in containers/growbags.

Sowing seeds

  • Sowing in mid-March to early April will give you a plant ready to plant out in late May.
  • Loosely fill a 10cm pot with fine ‘seed and potting’ compost. Slightly firm the compost to 1cm below lip of the pot. Water up carefully with clean water using a fine rose on the watering can. Make a hole in the compost and drop in one seed per pot about 1.5cm deep, cover with compost and water in with a fine rose.
  • In warm conditions (20-25oC) seedlings should emerge within 8-10 days. Use a heated propagator for best results. The enclosed atmosphere will maintain a high humidity during germination. When seedlings emerge, transfer to a bright greenhouse or sunny windowsill.
  • After germination, seedlings should be grown on at 20-24oC. Feed with balanced liquid fertiliser (according to manufacturer’s directions) after 2-3 weeks or if growth appears discoloured.

Store Bought Plants

  • Where a small number of plants are required, purchasing plants from the garden centre or garden shop is an option. Select healthy plants that are not wilting and are free from pests and disease.

Planting Outdoors

  • Only use varieties suitable for outdoor conditions. Ensure the plants have been acclimatised to outside conditions by hardening off plants, placing them outside during the day and protecting them at night until they have toughened up and will be able to withstand the colder outside temperatures. 

Planting Indoors

  • Use suitable indoor varieties. 
  • Plant out into growbags (2 plants per bag) or into soil, after roots have filled the pot and all risk of frost is gone.
  • Remove the pot and plant so that the top of the root-ball is about level with the soil or compost.

Watering and feeding

  • Water plants well every day.
  • Feed with a balanced feed at least once per week. Good levels of nitrogen and potash will contribute to vigorous plants which will produce many fruit. (Use fertiliser according to manufacturer’s guidelines.) 


  • Ridge/outdoor types: Can be left to trail on the ground or trained over a trellis. When the plant has produced 5 or 6 sets of leaves on the main stem pinch out the growing tip. This will encourage side shoots and therefore fruit. 
  • Indoor vine plants: To allow a strong root system to develop remove all side branches, flowers and tendrils on the first 100cm of the plant twisting the main stem clockwise around the support string.
  • Pinch out any subsequent lateral shoots at the first leaf. 
  • Remove the growing point of the main stem when a couple of leaves have developed above the overhead crop wire. Two side branches near the top of the plant are allowed to grow downward.
  • The growing point of each lateral is removed when about 30cm from the ground.
  • Fruits develop at the node of each leaf. The main stem is generally more productive than the two lateral shoots. Plants may set more than one fruit per node but these should be thinned to one to ensure better quality.


  • Cucumbers are ready to harvest when they are green, shiny and cylindrical in shape. If they are still pointed and not filled out at the end they are not quite ready. Use fresh or store in fridge.