Pumpkins are great fun to grow with children. They are easy to cultivate, but need a sunny position, plenty of water and shelter from cold winds. One of the finest sights of autumn is colourful pumpkins ripening in the sun – they are an essential part of Halloween and also attractive in the garden. Once harvested, pumpkins can be used for delicious soup and for roasting.
Pumpkins are best grown from seed indoors, but may be sown outdoors in the spot where they are to grow.
For earlier crops or in cold regions sow seeds indoors on their side 1cm (0.5in) deep in 7.5cm (3in) pots of compost from mid- to late April at 18-21°C (65-70°F).
If you don’t have the space to raise pumpkin seedlings, you can also buy young plants from garden centres in spring and these usually can be planted outdoors straight away (check with the shop when you buy them).
Sow two or three seeds 3cm (1in) deep outdoors in late May or early June and cover with cloches, jars or plastic; leave in place for two weeks, or as long as possible, after germination. Thin the seedlings to leave the strongest one.
Two weeks before planting or sowing seed outdoors, make planting pockets 1.8m (6ft) apart. Do this by making a hole about a spade’s depth, width and height and fill with a mixture of compost or well-rotted manure and soil. Sprinkle a general-purpose fertiliser over the soil. Plant one plant or seed on top of each pocket.
For indoor-raised seedlings, plant outside on top of your planting pocket in early June, hardening off (acclimatising) before doing so. Do this by moving them into a coldframe for a week or, if you don’t have a coldframe, move plants outdoors during the day, then bring in at night for a week. The following week, leave them out in a sheltered spot all day and night.
You can also grow pumpkins in growbags or containers (at least 45cm/18in wide). Plant one or two per growbag, or one per container.
Pumpkins need a sunny position, moisture-retentive soil and shelter from cold wind. As they need plenty of water, sink a 15cm (6in) pot alongside the plants when planting out. Water into this and it will help ensure the water goes right down to the roots and does not sit around the neck of the plant, which can lead to rotting.
Feed every 10-14 days with a high potash liquid fertiliser once the first fruits start to swell.
The fruit of pumpkins should be supported off the soil on a piece of tile or glass.
Troubleshooting Growing Problems
Powdery Mildew: Appears as a white powdery deposit over the leaf surface and leaves become stunted and shrivel.
Remedy: Keep the soil moist and grow in cooler locations.
No fruit, or fruit rotting when very small: This is a physiological problem, caused by the growing conditions, not a pest or disease. It is a problem when the weather in early summer is cool and this causes inadequate pollination.
Remedy: This is usually a temporary problem and once the weather starts to improve, so will pollination. You can try to hand-pollinate plants yourself by removing a male flower (no swelling at their base) and brushing the central parts against the centre of a female flower (female flowers have a swelling at the base – this is the beginning of the fruit). But this is a bit of a hassle, and normally the plant will correct this problem itself.
Grey mould: Can be a problem in densely sown crops, especially ‘cut and come again’ veg crops. Seedlings suddenly collapse. This is a problem normally in wet conditions, and is usually worse on weak or damaged plants. The mould usually enters through a wound but, under the right conditions, even healthy plants will be infected. You will see fuzzy grey mould on affected buds, leaves, flowers or fruit. Infected plant parts eventually shrivel and die.
Remedy: Sow thinly and when conditions are warm. Hygiene is very important in preventing the spread of grey mould. If you see it, remove the infected material and destroy. Grey mould is encouraged by overcrowding, so make sure you plant your seedlings, plants and squashes at the appropriate distance apart.
Let the fruit mature and colour on the plant and remove before the first frost strikes. If storing, allow skins to harden in the sun.
Plant with: corn, marigold, melons, nasturtium, oregano, squash