Pumpkins for Halloween start on a windowsill in April

If you want pumpkins for Halloween, sow them indoors in April. From late March to mid-April is ideal, which gives them time to grow on before planting out in May, and to swell and ripen by October.

Winter squash, such as butternut and crown prince, follow almost the same timing and grow the same way.

Sowing

Sow one seed per 8 cm pot, 2.5 cm deep. Keep it warm, ideally around 20 °C, and the seedlings come up within a week. Pot them on into larger pots if their roots fill the first ones before planting time.

You can also sow outdoors from late April to mid-May, two seeds per spot, under a cloche or a cut-off plastic bottle. Thin to the stronger seedling.

Planting out

Pumpkins are killed by frost. Plant out after hardening off for a week, from early May in mild areas, or later in May in colder ones. These dates are for a typical lowland garden in England or Wales, with a last frost around 20 April. Cover young plants with fleece if a cold night is forecast.

1. Pick the sunniest spot you have, out of the wind.
2. Dig a hole and fill it with well-rotted manure or compost. Pumpkins are very hungry.
3. Plant on a small mound, and water around it rather than over the stem.
4. Give each plant plenty of room: 120 cm between plants and about 180 cm between rows.

They grow well with sweetcorn and runner beans, an old pairing often called the three sisters. Nasturtiums and French marigolds also make good neighbours. Keep them away from potatoes.

Through the summer

Water well, especially when the fruit is swelling, and feed every couple of weeks with a high-potash liquid feed once the first fruits form.

The long trailing stems can be trained round in a circle to save space. Once two or three fruits have set on a plant, pinch out the stem tips so the plant feeds those rather than making more.

Slip a tile, a piece of wood or some straw under each fruit to keep it off wet soil, which can make it rot.

Harvest and curing

Pumpkins are ready from early September. Leave them on the plant as long as you can, but cut them by the end of October, before the first frost. Cut with a long stalk, as a pumpkin without one rots quickly.

To store them, cure them in the sun for about ten days, or in a warm room if the weather turns, until the skin is hard. Then keep them somewhere cool and dry. Well-cured winter squash keep for months.

Common problems

Powdery mildew. White leaves in late summer. Mostly cosmetic this late in the season.

No fruit. Early flowers are often all male. Female flowers, with a small swelling behind them, come later. In a cool summer, hand-pollinate with a soft brush.

Slugs. They take young plants overnight. Protect them for the first few weeks.

Pumpkins share a bed happily with sweetcorn, and their relatives the courgettes are sown at the same time. Set your own frost dates on the pumpkin page.