Watermelon
While challenging, growing watermelons in the UK is possible with care, especially in a greenhouse or poly tunnel. They need consistent warmth, sun, and water to produce their sweet, refreshing fruit.
Watermelon seeds
£2.99 in the shop
Calendar
Sow
April, indoors in a heated propagator or warm spot (20-25°C)
Plant out
Late May – early June, after all risk of frost has passed, ideally under cover
Harvest
Late August – September
Conditions
Sun
Full sun, 8+ hours a day
Water
Keep compost consistently moist; water heavily once flowers appear and fruit begins to swell
Soil
Rich, well-draining, slightly acidic to neutral (pH 6.0–7.0)
Spacing
90–120cm between plants
Containers
Possible in very large containers (50cm/20 inches +) with consistent watering and feeding
Indoors
Essential for reliable crops in the UK – greenhouse, poly tunnel, or very sheltered, sunny spot
Care and harvest
Feeding
High-potash liquid feed every 2 weeks once fruit starts to swell
Pruning
Pinch out growing tips after 3-4 fruits have set per plant; remove any secondary fruits that set later
Harvesting
Look for a dull skin, a yellow patch where it rested on the ground, and a hollow sound when tapped
Storage
Store at room temperature for up to 2 weeks, or in the fridge once cut
Good companions: Marigolds, Radishes, Corn