Hokkaido

Hokkaido squash is an annual. The plant dies after the first frost and is not overwintered. Harvest the ripe fruits before the first frost, when the stalk has turned woody and the skin is hard, store them whole in a cool, dry, dark place, and save seed from a well-ripened fruit for the next season.

Propagate Hokkaido squash from seed only. Vegetative methods are not practical with annual squashes. You have two options: start the seeds indoors from early April in pots (8 to 10 cm, low-nutrient compost, sown 1 to 2 cm deep, 2 seeds per pot) at 20 to 25 °C in a bright, frost-free place. The seedlings appear after about a week. After the Ice Saints (mid-May), the young plants go outdoors, with plenty of space (around 1.5 m), because Hokkaido sprawls widely. Alternatively, sow directly into the bed from mid-May, again 1 to 2 cm deep. You can collect your own seed from fully ripe fruits (hard skin, woody stalk): cut the fruit open, scoop out the seeds, rinse the pulp off in a sieve under running water, spread them out on kitchen paper and leave them to dry at room temperature for 1 to 2 weeks. The seeds are dry when they are hard and rattle when shaken. Stored cool (5 to 10 °C), dark and dry, they stay viable for several years. Choose open-pollinated varieties, because the offspring of F1 hybrids do not come true to type. Important for true-to-type seed saving: do not grow any other Cucurbita maxima varieties (e.g. giant pumpkin, buttercup squash) nearby in the same year, as bees cross freely within the species. Hokkaido does not cross with other squash species such as courgette (C. pepo) or butternut (C. moschata), however. Alternatively, you can pollinate by hand: in the morning, pick a freshly opened male flower, transfer the pollen to the stigma of a female flower that is still closed but about to open, and then close it again so that no foreign pollen gets in.