How to grow Winter Squashes

How to grow Winter Squashes from seed

Ensure a good crop of fully ripe squashes by sowing early to allow a long growing season. This is second in importance only to diligent site preparation. Sowings can be made under glass or indoors on a warm windowsill. Mid to late April is the time to sow, allowing a month of cosseted growth before the young plants are set out. Seedlings need a temperature range of 15-20°C to germinate effectively. An indoor windowsill won’t require any additional heat but a propagator will be necessary for greenhouse sowings. Sow seeds one per 7cm plastic pot, or into large module trays. Fill pots and trays with seed compost, lay the seeds flat on top then push them down into the compost with your finger. Place them to 1cm deep and cover back over. Give them a water and keep them snug until the sturdy seedlings appear in seven to ten days’ time. After the seedlings have emerged, continue to keep them in a warm, well-lit place and water to keep the compost moist. Once their first set of adult leaves has appeared, pot them on into 12cm pots.

One month after sowing, your young squash plants should be of a decent size and raring to head out into their prepared plot. Only transplant once the danger of any late frost has passed. This is normally around mid-May, though the availability of cloches or fleece to help new transplants along will bring peace of mind. Before planting out, harden plants off for a week by putting them outside for increasingly longer spells, leaving them out overnight in milder weather. A cold frame is a great help in this vital process.

Plant out by excavating a hole in the soil and delicately placing the rootball of your squash into it. Firm into place and give the ground a really thorough watering. A dusting of general fertilizer such as blood, fish and bone, lightly forked into the soil surface, will give plants a boost until their roots reach the goodness of all that locked-up compost or kitchen scraps. Space plants 60-100cm apart, depending on the variety. Don’t be alarmed if they sulk for a few weeks. This is quite common until temperatures pick up and the plants really get away.

Caring for your Winter Squashes plants + problems

When the leaves have turned a deep green you’ll know you have lift off and your plants will rapidly romp away! From this point the sprawling plants need very little care. In particularly hot summers it is worth laying down a mulch of organic material such as lawn clippings, rough compost or even strips of corrugated cardboard to help retain moisture. Leaves rapidly crowd out any patch of bare soil, so weeding is rarely a necessity.

Trailing stems can be trained up supports, lifting plants off the ground and out of the way. This works well but the ultimate yield of fruits may be slightly compromised as the trailing stems will be unable to lay down new roots as they extend. Alternatively, allow the stems to sprawl on the ground, gently encouraging them into unused crannies. If you want extra-large fruits, cover the leaf axes of fruit-bearing stems over with soil or mulch to encourage further rooting and, hence, more resources to draw on. Additional feeding should be unnecessary if the soil has been well prepared.

How to harvest Winter Squashes

It is not uncommon to completely lose sight of which plant is which as they intermesh and sprawl into a jungle of stems and leaves. Thankfully, you won’t have to, as all winter squash varieties may simply be left where they are until the leaves yellow and die back in autumn to reveal the fruits beneath. Leaves may become infected with mildew as the weather turns cooler and wetter in September, but this isn’t a concern – the squashes will be unaffected and the leaves can stay in place.

If slugs are a problem, lift squashes off the ground and onto tiles or paving slabs to keep them dry. The fruits will be ready to harvest after the long summer by about mid- to late October. A mild frost won’t damage properly ripe fruits, but leaving them out in the open much longer risks compromising their storage potential.

Curing squashes

Winter squashes are one of the most useful vegetables on the plot thanks to their tough outer skin that gifts them with phenomenal storage ability. Prepared and stored correctly, there’s no reason a squash harvested in autumn shouldn’t keep until spring, offering a welcome source of warming goodness right through the colder months.

The secret lies in making sure squashes are fully cured before storing – simply hardening off the outer skin to protect the flesh within. Squashes should naturally cure outdoors in the early autumn sunshine, but if a particularly wet and cool spell develops, harvest the squashes a little earlier, say early October, and bring them under cover to finish off. A well-ventilated greenhouse or conservatory would be ideal. Eat up any that remain soft by November and keep the rest. Unlike other vegetables, winter squashes can store up to a cool room temperature. Anywhere from a frost-free shed to an unheated spare room would make a suitable winter store. The longest-lasting fruits will keep until early April.

Varieties of Winter Squashes

Winter Squashes varieties to try