Mid to late spring indoors, with the warmth specified on the seed packet.
After cold conditions have passed; greenhouse cucumbers are tender.
Summer and early autumn. Pick young, before fruits become oversized.
Choose a greenhouse variety
Greenhouse and outdoor ridge cucumbers can have different pollination requirements. Some greenhouse varieties are all-female. Follow the variety instructions on male flowers rather than applying one rule to every cucumber.
Raise sturdy plants
Sow into individual pots to minimise root disturbance. Keep seedlings warm and bright, and plant on before their roots become cramped. Set them at their existing depth, keeping the stem base clear of persistently wet compost.
Support and water
Provide a strong support before growth accelerates. Tie in stems loosely and follow the variety’s training guidance. Keep compost evenly moist and feed as directed once cropping begins. Water the root zone rather than leaving foliage wet overnight.
Harvest and troubleshoot
Pick regularly with clean secateurs. Inspect for aphids, whitefly and red spider mite, particularly during dry heat. Bitter fruit can have several causes, including the variety and growing stress; check the packet and keep care consistent.
Plan the next step
Keep a weekly record of watering, feeding and harvests. Note your overnight minimum temperature: this is more useful than the warmest afternoon reading when deciding whether a tender crop can move into an unheated greenhouse.
Read the monthly growing calendar, watering and feeding guide and plant health guide alongside your seed packet.
Further reading: RHS greenhouse vegetables.
What’s happening in your greenhouse?
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