What to plant in June

How about pumpkins? Yes, you’re more likely to associate them with the dark nights around Halloween than the sunny days of June, but early June is your last chance to sow pumpkin seeds so that they have enough warm days to develop size and good flavour and be ready to harvest in September and October.

Large pumpkin cultivars are often bred for size alone, so if you're growing pumpkins to eat, you need to make sure you’re choosing a cultivar that's known for flavour.

Pumpkins and squashes come in a whole variety of shapes and sizes, from traditional Halloween pumpkins and butternut squash to more unusual varieties such as 'Turk's Turban' and 'Crown Prince'. A very versatile fruit, pumpkins and squash can be boiled, steamed, roasted, used in stews and curries or blended to make a delicious autumn soup. Dried pumpkin seeds can also be eaten. Most varieties store for up to a few months, so you can enjoy them through most of the winter months.

You can either sow the seeds directly into fertile soil enhanced with well-rotted manure or peat-free multi-purpose compost, or into individual pots to plant out when the seedlings are large enough to handle. Soak the seeds in water overnight to speed up germination, and plant them on their sides rather than flat to stop water sitting on top and causing them to rot. Water them in well.

Choose a sheltered, sunny spot for their final growing position and plant them at least 90cm apart, according to the variety. Cover the surrounding soil with a mulch of garden compost to retain moisture, and a cloche to ward against slugs and snails. Inserting a bamboo cane next to each plant will help you find its centre for watering, no matter how large the plants grow. If growing from seed is not your thing, plug plants can also be bought and planted out this month too.

After planting, pumpkins and squash plants will grow quickly. Depending on how much space you have, you can either let them trail over the ground or train them up a support. Stems touching the ground can be pegged down to encourage them to root down into the soil.

Pumpkins and squashes have separate male and female flowers. You can tell them apart as the female has a swelling behind it, which is the immature pumpkin or fruit. The fruits will only develop if the female flower has been pollinated. In cold or wet summers you might need to make sure this happens. To pollinate the flower yourself, remove a male flower and insert it into the female flower to transfer pollen from the stamen onto the stigma.

You need to keep the ground weed free while the plants are small, but once they get going the large leaves will prevent any weeds from growing. Water plants regularly, especially in dry weather as dry soil encourages powdery mildew. As the fruits start to swell, lift them gently onto a brick or straw, so they don't ripen on the ground.

Cutting away any foliage shading the fruits will help them ripen. Harvest them before the first frosts in October and November when the stem connecting the fruit to the plant begins to crack. Cut the stem as long as possible. Pumpkins and squash keep best if you leave them in the sun for about 10 days before storing, as this toughens the skin, helping to prevent them drying out in storage. Remember to cover them on frosty nights, then put them somewhere cool, dry and well ventilated. They should keep for about six months.

Great pumpkin and squash varieties to grow include:

• ‘Baby Bear’ - a compact pumpkin, perfect for smaller gardens

• ‘Sprinter’ – a fast-maturing butternut squash with sweet, firm flesh

• ‘Crown Prince’ – a prolific cropper with delicious, blue-grey skinned fruits

• ‘Hasta La Pasta’ – a yellow skinned squash with noodle-like flesh

• ‘Sunshine’ – a winter squash with a deliciously sweet, nutty flavour

• ‘Turk’s Turban’ – a decorative squash with orange and green flesh