Butternut Squash

Overview:

 Butternut squash is a type of winter squash. Winter squash requires a longer growing season than most other garden vegetables. Winter squash will require some patience, but it is well worth the wait. 

General Plant Information:

• Common Name: Butternut Squash

• Scientific Name: Cucurbita moschata 

• Planting Zone: 3-10

• Plant Type: Annual

• Pot size: 24 inches or greater

• Days to Germinate: 7-14

• Planting Depth: 1 inch

• Seed Spacing: 24 inches

• Sun Requirements: Full sun

• Water Requirements: Moderate 1 inch per week

• Plant Size: 3 feet

• Days to Harvest: 75-100

• Harvesting Code: Green (easy difficulty)

• Growing Code: White (easy difficulty)

Planting Instructions: 

• Plant squash in a location with full sun and lots of space for sprawling vines. Most full-size winter squash varieties need 75 to 100 square feet to spread. The soil must be well-fed and moist (not soggy), and well-draining. Mix aged manure and/or compost (about 50% native soil to organic matter) deep into the soil a couple of weeks before planting.

• Direct-sow (plant seeds directly in the ground) when all danger of frost has passed, and the soil is at least 60°F, preferably 70°F.  Squash are very sensitive to the cold.

• If you have a short growing season, start seeds in peat pots 2 to 4 weeks before your last spring frost date. Squash seedlings do not always transplant well, so handle the roots gently.

• If you plan to grow only a few plants, use 2 to 3 tablespoons of a balanced (10-10-10) fertilizer for each hill. Scatter the fertilizer evenly over a 2-foot by 2-foot area. Work it into the top 3 to 4 inches of soil. Or, for a larger garden area, add 2 to 3 pounds of balanced fertilizer for every 100 square feet.

• Sow seeds in level ground 1 inch deep with seeds 2 to 3 feet apart. Or, sow 3 to 4 seeds close together in small mounds (or hills; the soil is warmer off the ground) in rows 3 to 6 feet apart.

• Consider planting a few squash seeds in midsummer to avoid problems from squash vine borers and other early-season pests and diseases.

• The seeds should germinate in about a week with the right soil temperature (70ºF / 21°C or more). 

• If necessary, use row covers or frame protection in cold climates for the first few weeks of spring. 

• Use row covers to prevent insect problems early in the season Remember to remove covers before flowering to allow pollination by insects.

Growing Information: 

• Use mulch to discourage weeds, retain moisture, and protect shallow roots.

• Water thoroughly, frequently, and consistently, with at least 1 inch per week. Water at the soil level and try to keep leaves and fruit dry. Dampness will make root rot and other diseases more likely.

• When weeding around squash plants, do not over-cultivate, or the squash’s shallow roots may be damaged.

• When seedlings in rows are 2 to 3 inches tall, thin to one plant every 18 to 36 inches by snipping off unwanted plants without disturbing the roots of the remaining ones.

• When seedlings in hills are 2 to 3 inches tall, thin to 2 to 3 plants per hill by snipping off unwanted plants without disturbing the roots of the remaining ones

• When the first blooms appear, scratch about 2 tablespoons of all-purpose fertilizer around each hill. Or, if growing squash in rows, side-dress. This gives plants a boost as they try to produce fruit or blooms. Do not let the fertilizer touch the plants. Water the plants after fertilizing.

• Once vegetables or flowers start growing and producing buds, you can scratch a small amount of all-purpose organic fertilizer into the soil around the base of the plant and water in.

• Pruning the vines will help with space, as well as allow the plant’s energy to be concentrated on the remaining vines and fruit.

• Poor pollination can result in squash flowers that do not bear fruit, or that bear small fruit. Pollinator activity is reduced by any chemicals, poor weather at bloom time, and lack of habitat. To attract more bees, try placing a bee house in your garden or plant-pollinator flowers nearby.

• If your first flowers aren’t forming fruits, that’s normal. Squash plants have separate male and female flowers. Males appear first on long thin stalks. Female flowers follow with an immature fruit at the bottom. To fruit, pollen from male flowers must be transferred to the female flower by bees. Or, the gardener can help manually with a cotton swab or paintbrush. 

Harvesting:

• Winter squash are generally ready to be harvested in early- to mid-autumn, usually late September through October.

• Unlike summer squash, which is harvested when tender and a bit immature, harvest winter squash when it is fully mature. The vine leaves die back and turn brown, the stems dry out and get tough, and the rind is deep in color and hard. If you can pierce the skin with your fingernail, it is not mature. 

• Harvest on a dry day after the vines have died back.

• Leave an inch or two of stem on winter squashes when harvesting them.

• Cut the squash off the vine carefully with a sharp knife or pruners; do not tear, as you could break the fruit stem or the vines. 

• Never carry the squash by their stem; if the stem breaks off, this exposes the skin to infection. 

• Once you harvest, don’t forget to clean up the old squash vines to avoid disease! Add vines to the compost pile if you have one. They’ll break down, and you can work the compost into the soil before the next planting season.

• Remove the seeds from the squash and wash them to remove all fleshy strings. lay the seeds on a paper towel to dry for 3-7 days.

• Store the dried squash seeds in an air-tight container in a dark, dry place at between 50-55 degrees F.  

Resources:

Stillman, J., Pierce , S., Hale , J. D., Burnett, J., Stonehill, H., Perreault, S., Boeckmann , C., Quinnell, C., Burnett, C., Korpi, S., & Edson, J. (2022, June 3). How to Plant, Grow, Harvest, and Cure Winter Squash. Almanac.com. Retrieved April 12, 2023, from https://www.almanac.com/plant/winter-squash