Squash 'Buttercup' is a variety of winter squash that's considered the sweetest of squash. The plants produce an unusual shaped, flattened globe shaped, dark green striped fruit which covers a bright orange, creamy interior.
A Japanese kabocha-type squash it produces attractive green, slightly ribbed fruits each with a distinctive blossom-end button and flattened turban shape.
Buttercup squash can be used in any recipe calling for butternut or acorn squash. They can be prepared as main courses, salads, side dishes or desserts. One of the advantages of using these varieties, besides their sweet nutty flavour, is their texture, they are known for their drier flesh. They hold their shape in stews and curries, and if used raw and grated into a winter salad, they’ll add a sweet crunch and burst of orange colour.
The delicious dense firm flesh has a superb sweet flavour which is beautiful cut into slices and steamed gently until tender. With a weight at around 1.5kg, use for roasting with the joint, soups and pumpkin pie.
The thin, hard rind surrounds orange flesh that is sweet, stringless and highly desirable - so sweet it can actually be used like a sweet potato. It's perfect mashed, pureed, steamed, or as a sweet potato replacement in most recipes. Buttercup squash are perfect for filling and roasting, turning them into beautiful bowls with grains, sage and more veggies is a full sensory experience.
Prepare the Site:
Choose a sunny, sheltered spot with moisture retentive, humus rich soil. Improve the soil by digging in some well-rotted manure or compost. The simplest way is to dig a hole 30cm (12in) deep and 45cm (18in) across and fill it with well rotted compost or manure. Cover with a 15 to 20cm (6-8in) layer of soil to make a raised mound that will provide drainage along with a rich source of nutrients. Left to their own devices the plants will trail for several feet in all directions. Ideally each plant needs 120cm square (4ft square) in order to spread and avoid competing with nearby plants. (Alternatively you can grow them in large containers).
Sow indoors in pots April to June or sow direct from mid May to the end of June.
A minimum temperature of 10°C (50°F) will be needed for germination, which can be supplied in the greenhouse, glazed porch, or cold frame.
If grown entirely in a heated greenhouse seed can be sown in situ in late winter, or early spring for transplanting to a cloche or cold frame. If you do not have any glass, then delay sowing until late spring to avoid damage from heavy frost.
Fill 7.5cm (3in) pots with compost and firm gently. Sow seed on its side, not flat to ensure reliable germination. Sow 12mm (½in) deep and cover. (You may choose to sow two seeds per pot, and remove the weaker seedling later; the strongest plants are kept.) Label, water and put in a propagator or on a windowsill.
Germination should take place 10 to 14 days later. If temperatures are higher it may only be 4 to 6 days. After germination the young plants will grow very quickly and will need repotting almost at once. When roots begin to show through the bottom of the pot, transplant to a 12.5cm (5in) container. Keep barely moist to prevent stems from rotting and protect from strong sunlight with a sheet of newspaper.
Hardened off before planting outside, around late May/early June and all danger of frost has passed. Plant out with 120cm (48in) between plants, providing good air circulation to avoid mildew. Protect seedlings from slugs
Sowing directly outdoors:
Early sowing outdoors is rarely of much benefit as the seeds may not germinate if the soil is too cold, or cold temperatures may damage young plants. Four weeks before the last frost is expected is about right.
Sow two or three seeds 2.5cm (1in) deep on their edges under cloches or glass jars with 45 to 60cm (18 to 24in) between plants. Remove the weaker seedlings later.
Hoe gently to keep the weeds down and do not let the plants dry out. Plenty of water is essential, especially when the plants are in flower and when the fruits have started to swell. Avoid splashing water on the stems of the young plants. Apply a mulch of about 12mm (1in) deep of grass cuttings or compost after watering. This helps conserve soil moisture and keeps the weeds down.
If you dig in plenty of manure before planting, additional feeding is unnecessary on heavy, fertile soil. On sandy or light soil, regular liquid feed will help boost production.
Plants under glass should be hand pollinated. The female flowers are distinguished by the swelling below the bloom. Male flowers have a prominent central core, bearing yellow pollen. The male flower is first to appear and the female flowers will follow. To hand pollinate, remove the petals from a male flower; push the core into the centre of the female flower. For a high success rate, use a different male for each female flower.
Harvesting: 80 to 95 days (11 to 14 weeks.)
Unlike summer squashes, such as courgettes and marrows, it pays to let winter squashes ripen thoroughly. If you harvest the fruits regularly you will get a heavier crop over a longer season.
You will know that your plants are ready after the rind of the vegetable has hardened and the stem is two inches long. If you harvest it before it is fully mature it will lose its sweet flavour. Harvest before the temperature falls. Use a sharp knife or secateurs to sever the fruit from the plant leaving a short stem, do not pull them off. Harvest all fruits before heavy frost, and they can be stored indoors at 10°C for several months.
Before storing, cure the fruit. Curing is best accomplished by allowing them to remain in the sunshine for about ten days. It is the sunlight that cures or hardens the skin. If there is a chance of freezing weather, protect in a storage building and return to the sunlight the following day.
If you cure the fruit and store them properly, they will last well into the winter. The storage area should be dark, about 10°C (50°F), and rather dry (less than 65% humidity).
The first buttercup, ‘Burgess Buttercup’, was developed in 1925, the result of an accidental cross between ‘Essex Hybrid’ and ‘Quality’. ‘Essex Hybrid’ is an orange, slightly squared, turban-type squash that was found in a field of ‘American Turban’ in 1879.
Buttercups were developed by breeders at North Dakota State University. Buttercups typically have thick, dark-green skin with light stripes and a blockier shape than kabochas. Their flesh is orange-yellow, sweet and dry, though not as dry as the flesh of kabochas. Most Buttercups have a protruding lighter grey-green 'button' surrounded by a circular scar at the blossom end of the fruit. In spite of their differences, kabocha and buttercup squash are often considered to be a single type in marketing and breeding, and the terms are sometimes used interchangeably.
- Additional Information
Packet Size 2 grams Average Seed Count 15 Seeds Common Name Japanese kabocha-type squash Other Common Names Winter Squash Other Language Names JP: Seiyo Kabocha Family Cucurbitaceae Genus Cucurbita Species maxima Cultivar Buttercup Hardiness Half Hardy Annual Flowers Bright yellow flowers Natural Flower Time Summer Position Choose a sunny, sheltered spot Soil Moisture retentive, humus rich soil. Time to Sow Sow indoors in pots April to June or sow direct from mid May to early June. Germination Germination of seeds is about 2 weeks Harvest Use pruning shears or a sharp knife and leave 7 to 10cm (3 to 4in) of stem Time to Harvest Matures in 85 days.