Smashing pumpkins: celebrate winter squash Squash today The butternut, often seen in supermarkets, is a custard-coloured pear-shaped squash originally from Guatemala and Mexico. It needs lots of heat, although there are now faster-maturing, vigorous British F1 varieties bred by Jamie Claxton of Tozer Seeds. 'Hawk," 'Hunter" and 'Harrier" performed well at RHS Wisley in Surrey, winning three Awards of Garden Merit (AGMs) in the 2008 trial. 'Hunter" was the most prolific of the three, yielding an average of seven squashes per plant; 'Hurricane" is coming shortly. However, all of these have failed in my cool Gloucestershire garden. Robin Bartels of Tozer Seeds explained that breeding work continues, but so far commercial growers north of Cambridge opt for other varieties, such as kabocha. The butternut squash (JONATHAN BUCKLEY) Luckily I do very well with orange kabocha squashes. These were originally brought into Japan from Cambodia by Portuguese sailors in 1541 and the Portuguese name, Cambodia abóbora, was corrupted to kabocha. Two I rate highly are 'Sunshine" (bred by the American seed company Johnny's Selected Seeds in 2004) and the smaller-fruited 'Sunspot" from Rupp Seeds of the US. Both were AGM winners in the 2010-11 winter squash trial. Sunshine" (from T & M) has been the tastiest of the many squashes I have grown over the past seven years. A good summer will yield six fruits with an average weight of 3lb-4lb each. Sunspot" (available soon) bears smaller fruit, but still has an excellent flavour. 'Golden Queen" looks just like 'Sunshine" but has a disappointing flavour. The red onion squash, 'Uchiki Kuri," is sometimes known as the orange hokkaido squash. It also crops well, even in cool summers, and in a hot season will produce eight fruits per plant. On average, fruits weigh just over 2lb, a good size for one meal. 'Kuri" is Japanese for chestnut and 'Potimarron" (another red kuri) means "chestnut pumpkin" in French. They are similar to each other, but 'Potimarron" produces larger fruits of roughly 3lb each, but perhaps the flavour is not quite as good. Just to confuse matters, in the US orange kuri kabochas are called buttercup squashes - a term now finding its way into our seed catalogues. Mother Hubbard Some winter squashes have grey skins and redder flesh and these are developed from the 'Blue Hubbard," an enormous teardrop-shaped squash which is thought to have arrived from South America in the 1700s. It was grown by American Indian tribes and then by settlers. In 1842, a woman named Elizabeth Hubbard mentioned the squash to her neighbour, a seed trader named James J H Gregory. Mr Gregory marketed it and named it the Hubbard squash. At our last weigh-in, this misshapen giant was over 15lbs and could have fed an army. 'Crown Prince" AGM has all the 'Hubbard" flavour and durability, but this round grey-skinned squash weighs in at a more manageable 7lb. Grey-skinned Hubbard types crop well in Gloucestershire and store for longer than orange-skinned squashes. However, the Hubbard types have thinner skins and can get frosted more easily - so be careful where you store them. Once a squash is cut it will keep in the fridge for weeks. If you haven't added winter squashes to your seed list, give them a try. Sowing squash seed Mid-March is usually ideal for sowing in an unheated greenhouse. However, in a cool spring an electric propagator helps greatly. The Vitopod electric propagator is excellent (0845 602 3774; greenhousesensation.co.uk). There is no need to chip or soak the large, oval seeds as they germinate easily in warmth and light. However, they can rot if laid flat on the surface of the compost. Place them vertically, pointed end downwards, pushing them about half an inch into three-inch round plastic pots with seed compost. Label clearly. After sowing, water them thoroughly. Then leave them alone until the seeds have germinated. Once they are up, water the seedlings in the morning. Fleece the plants if a cold night is forecast. Pot up into larger pots once the roots fill the three-inch pots, using John Innes No 3. Don't plant them outside straight from the greenhouse. Harden them first by placing them outside for 10 days, before planting them. Squashes in the garden Squashes need a warm, sunny position and fertile ground. Add as much compost as you can spare. Water plants in their early stages. Once the leaves get larger they cover the ground and keep moisture in. Feed them. Chicken pellets work well and they can either be dug into the ground before you plant, or sprinkled on as you go. Wait until the after the first week of June before planting outside, as the slightest frost will catch them. Cover the plants with heavyweight plastic bell cloches. This will double their size within days as squashes only photosynthesise in warm temperatures. Harvesting and storing Harvest in September once the stem has become corky and woody. Ripen the squash for a couple of weeks outside in a warm, sunny position, stem downwards. Bring them into a cool, dry shed or outbuilding and store them for at least four weeks before eating. Know your squash Sunshine A Japanese round, orange squash with a superb flavour (Thompson & Morgan only). Uchiki Kuri The Japanese red onion squash, round and orange with an excellent flavour. Crown Prince A silvery-grey squash with bright orange flesh. Potimarron An orange teardrop squash that originated in China, despite its French name. Good chestnut flavour. Thompson & Morgan (0844 248 5383; thompson-morgan.com) Plants of Distinction (0844 856 0763; plantsofdistinction.co.uk) Suttons (0844 922 0606; suttons.co.uk) Mr Fothergill's (0845 371 0518; mr-fothergills.co.uk) The Organic Gardening Catalogue (01932 253666; organiccatalogue.com) READER OFFER 'Butternut" is a highly popular variety of winter squash known for its heavy, elongated pear-shaped fruits. Buy one packet of approx 15 seeds for only £1.49, plus £1 p & p. Visit gardenshop.telegraph.co.uk/offers.