Butternut Squash

Butternut squash (Cucurbita moschata) is a warm-season vine that trails along the ground or climbs using tendrils. Its fruits have a hard rind, and both the fruits and seeds are edible. The plant suits large spaces best, though it also does well in vegetable gardens and on trellises. It grows aggressively, so home gardeners may want to avoid very vigorous commercial varieties that produce huge vines.

Sow seed directly in the garden when the soil is warm, because this squash is easily grown from seed in warm soil. Choose a spot in full sun with fertile, moisture-retentive but well-drained soil. Sow the seeds on their side about 1 cm (⅜ inch) deep. If you start seeds indoors, sow them in good quality seed compost from March to May and keep the temperature at 18 to 21 °C (64 to 70 °F). You can also transplant seedlings in late spring, early summer, or after the last frost.

Give the plants full sun, which means at least 6 hours of direct sunlight a day. Keep the soil moderately moist and aim for a soil pH between 6.0 and 8.0. Feed the plants regularly with a high potassium fertiliser once the first fruits start to swell. No pruning is required.

Slugs, aphids, and beetles can be problems. Another guide says the plant is generally pest-free, but it may be susceptible to grey moulds and powdery mildews.

Fruits mature from late summer into fall. A mature squash has a hard skin that can’t be punctured with a thumbnail and a uniform tan color. When you cut the fruit from the vine, leave about 1 inch (2.5 cm) of stem attached.

After harvest, cure the squash at 80 to 85 °F (27 to 29 °C) and 80 to 85 percent humidity for 10 to 14 days. Then store it in a cool, dry, well-ventilated place at 50 to 55 °F (10 to 13 °C). Keep it away from apples, pears, and other ripening fruit, because ripening fruit release ethylene gas that shortens storage life. When properly cured and stored, it keeps about 2 to 3 months.

If the fruit tastes bitter, don’t eat it or feed it to pets. Wear gloves and other protective equipment when handling the plant.