Pumpkins are members of the Cucurbitaceae family which also includes: Cucumbers, Gourds, Squash, Melons and Courgettes & marrows. These half-hardy annuals make good potager plants because not only are they a great food source over the winter months but the leaves and flowers are attractive as well as the fruits. Most cucurbits will either trail over the ground or climb over supports. Supported they take up less space and the quality of the fruit is better, they can also provide shade for more delicate leafy plants during the summer months. Plant cucurbits to climb over walkways, pergolas, trellises, posts, bean poles and fences.
If you want a bumper crop, pumpkins need space. For our needs we don’t need that many so I prefer to stuff them in wherever I can; on the edges of beds to run under large brassicas or corn or to grow along perimeter fencing or over trellicing. As a general guide at a minimum plant bush varieties about 75cm (2ft) apart and trailing varieties 3-4ft apart or give them more space and plant bush varieties 1.5m (3-5ft) apart and trailing varieties 2-2.5m (6-8ft) apart. Allow plenty of room for the plants to spread or climb.
Site & Soil
Pumpkins are fairly greedy and thirsty plants requiring well drained, moist, rich soil in full sun. Cucurbits require a growing season of 3-4 months with a mean monthly temp of 18-27c. Minimum soil temp should be 13c. Avoid cold sites and exposed positions. To prepare a cucurbit bed: Dig out planting holes at your chosen spacing at least 30cm (1ft) deep and 45cm-60cm. Work-in a bucket-full of compost/manure. Return topsoil leaving a shallow depression in the top. Form a ridge 5cm (2in) high surrounding each planting hole to help retain moisture.
Most cucurbits will not transplant very well so in warm conditions it is best to sow direct. However if you want to get an early start or the beds are not free yet you can sow in pots undercover and plant out to minimise root disturbance.
- Sow undercover 3-4 weeks before the last frost is expected, (at the same time the planting holes are being prepared outside). Sow seeds, on their side, in a good free draining seed compost in 7.5cm biodegradable or plastic pots, 2 seeds per pot . Apply a layer of compost or vermiculite, 1cm (½in.) deep. Place in a propagator or polythene bag until the seeds germinate. Thin out the weeker seedling. When the remaining seedling has 3-6 true leaves and the roots have filled the pot (usually after 2-3 weeks). Harden off (1-2 weeks in a cold frame or in a sheltered spot) and plant-out once all danger of frost has past, to the level of the soil in the pot. The neck of the plant can be vulnerable to rot so should not be buried.
- Sow in plugs – curcubits grow well in the little pucks availble from gardening shops. Hydrate the pucks and sow one seed in the centre of each, press the sides to cover and keep moist at all times. When the roots appear at the edges of the puck plant out or on into a pot and treat as above.
- Sow direct when the soil has warmed up and all danger of frost has past, in our area that is early May. Sow 2 seeds (1in deep) into each of your prepared planting holes. Cover with a mini cloche (a cut down water bottle) if necessary for protection. When the plants emerge thin to the strongest.
Germination at 20-30C usually takes 5-10days. Seeds can be soaked over night to aid germination or chitted and sown when sprouted. Seeds should be sown on their sides not flat.
Pollination Male and female flowers are usually born separately and are insect pollinated. The female flower can be distinguished by the tiny bump behind the petals which develops into the fruit after fertilisation. Hand pollination may be necessary if fruits fail to set (best done in the morning).
Planting by the moon
Sowing at the optimum point of the lunar calendar really does seem to make a difference to Cucurbits. In our small scale trials cucurbits have germinated significantly better when sown 1 day before a full moon.
Water-in thoroughly after planting out. Water regularly and liquid feed (seaweed) every 14 days once fruit start to develop. Mark the position of the plant, with a tall stick, as it can be difficult to see where the root of the plant is when in full growth. Train Tie into supports if growing up and If growing on the ground train the leading shoot to grow in a circle, it looks great saves space and can increase plants food supply. Pin down the stems / or bury at intervals the cucurbit should develop roots on the stem thereby increasing food intake. Prune Fruits develop on laterals as well as the main stem so if the plants become too rampant nip out the main growing point and cut back laterals to within a couple of inches of the nearest developing fruit. Thin small fruit and use them in the kitchen to encourage larger fruit later. MULCH Make sure supports are strong enough to take the weight of the plant and be prepared to individually support the larger fruit if necessary.
Companion: Cucurbits tend to grow well with; beans, peas, sweetcorn, capsicums, nasturtium but mostly do NOT grow well with potatoes. Plant flowers around Cucurbit beds to encourage pollinating insects.
Harvesting and Storage
Because Pumpkins store so well they are an excellent source of food over the winter months. On average they will keep for 6months but some store for 12 months or more. Store in well ventilated conditions at temperatures between 7 and 16c. At higher temperatures they will dry out. Pumpkins can be used immature cutting early will result in a heavier crop for winter but when harvesting for winter storage they must be harvested mature.
Signs of maturity are:
- Skin colour changing from light to dark some green types may also loose their gloss.
- Stalks become corky and dry (about 50% brown is a good sign of maturity.
- Skin cannot be pierced with a thumb nail.
- Flesh is orange rather than yellow and the seeds are hard.
- Cracks appear on stems and skins
Leave on the plant as long as possible but bring in before 1st frost. Cut with 3-5cm (1-2in) of stalk. Cure in a sunny sheltered position (27-32c) (e.g. against a sunny wall) for 4 -10days to allow stalk to seal and skin to harden. Protect from night frost.
Nutrition and Culinary
Pumpkins have a higher nutritional value than courgettes and marrows (summer squash) and the Cucurbita moschata have a particularly high Vitamin C content 30% more than maxima and 80% more than pepo. Pumpkins are pretty versatile they can be used in both savory and sweet dishes. As a vegetable they can be pureed, cut into chunks and stir fried, deep fried, boiled or stewed. They can be added to soups and casseroles or cooked with mustard greens. They can be made into excellent sweet pickles, the ripe seeds can be roasted as a snack or added to salads and the flowers are a delicacy. Pumpkin seeds are a good source of essential fatty acids, potassium, and magnesium.
There are so many varieties of pumpkin it is impossible to grow all of them in one life time, but here are some of my favourites so far. I tend to prefer the dryer nuttier types of pumpkin.
reliable large cropper, creamy ochre smooth skin with a pear shape, flesh is golden-orange with a lovely hazelnut flavour. Fruit are high in Vitamin C. Great roasted, pureed or in stews, curries etc. Keeps 12months. Seed source: from organic seeds given to me by another organic grower.
Green Hokkaido (maxima)- pictured above
fattish round pumpkin with slight ribbing, dark green skin with a dense, nutty, dry, yellow to orange flesh. Each plant produces 1-3 fruit around 13-25cm in diameter with an average weight of 1-2.2kg. Matures in 98 days from direct sowing. Keeps well, 9-12months. Source Ferme St. Marthe
Marina di Chioggia (maxima) – pictured aboveItalian Heirloom – magnificent to look at, dark green knobbly skin with deep yellow orange flesh, growing up to. 5kg. lovely baked. Stores well 9-12months and flavour often improves with age. Seed source: Seeds of Italy, Seeds of Kokopelli, Ferme St. Marthe
Potimarron Red Kuri (maxima) A Japanese ‘Orange Hokkaido’ type pumpkin also known as Uchiki Kury. Brick-red tear drop shaped fruits weigh in at 1.5-2.5 kg and an average diameter of 15cm. They have a wonderful dense dry flesh and a deep chestnut flavour. Stores 4-6 months. pictured above
Potimarron (maxima) originally brought from Japan by Macrobiotic master Oshawa. Now a French classic. Chestnut flavoured dense flesh 2-4kg Keeps fairly well, 4-8 months. Matures in 90days from direct sowing. Seed source: Seeds of Kokopelli, Ferme St. Marthe
Blue Hubbard (maxima) Huge, teardrop-shaped fruit weigh 15-40 lbs and have sweet, fine-grained, golden flesh. Great for baking, pies, and soup. The hard, blue-gray shell helps these keep for long periods in storage. Gregory Seed Company introduced this fine New England variety in 1909, and Mr. Gregory considered it his best introduction. pictured right
Musquee de Provence (moschata) French southern heirloom variety smooth skin, green ripening to ochre with deep ribs and sweet, aromatic firm orange flesh, They look a bit like a Cinderella pumpkin. Vines are vigorous and can grow up to 6m bearing 2-5 9kg fruit. Matures in 110days from direct sowing. Keeps well.