How to Grow Butternut Squash

Grow this winter squash from seed and enjoy a nutritious harvest

Butternut squash laying on bed of straw with leaves

The Spruce / Steven Merkel

Butternut squash (Cucurbita moschata) is a type of winter squash. The fruit starts out with a light green skin, but its skin, or shell, turns beige when the squash is ready to be harvested in fall. The flesh is dense and rich-orange in color. Some people roast butternut squash and use it in soups, while others boil it, mash it, and serve it in place of mashed potatoes. This nutritious vegetable (technically a fruit) is high in vitamin A.

Butternut squash plants are annuals that grow in almost any climate. They are planted in spring, following the last frost of the season. Their vines grow quickly, but the fruits may not be ready to harvest for three to four months from planting time. For smaller space gardens, bush varieties of butternut squash are also available.

Botanical Name Cucurbita moschata
Common Names  Butternut squash, Butternut pumpkin, Gramma
Plant Type Annual
Mature Size 9-18 in. tall, 10-15 ft. wide (vine length); bush varieties take up less space
Sun Exposure Full sun
Soil Type Rich, well-drained
Soil pH Acidic to neutral (5.5 to 7.0)
Bloom Time Summer
Flower Color Yellow
Hardiness Zones 2 to 11 (UDSA)
Native Area Central America, South America

How to Plant Butternut Squash

If you want an instant garden, you can sometimes find butternut squash seedlings for sale in biodegradable pots at the garden center. Biodegradable pots break down naturally when planted in the ground, so the plant's roots aren't disturbed. Butternut squash also is very easy to grow from seed.

Commonly, gardeners plant butternut squash on 'hills" in groups of three. The soil is mounded slighting to allow good drainage and to let vines run. Hills should be spaced at least 8 feet apart with rows 3 feet apart. However, if planting bush varieties, they can be planted 3 feet apart. Amend the soil ahead of time with organically rich ingredients, such as compost and composted manure, as winter squash is a heavy feeder. Plant seeds 1/2 to 1 inch deep, in groups of four or five seeds. When the seedlings emerge, thin them to the spacing interval specified for the variety.

When the seedlings are young, they are susceptible to drought (so keep their soil moist) and to damage from slugs and snails. Be sure to take control measures against these pests. Later in the season, Japanese beetles can become a problem. Pick them off by hand and throw the beetles in a bucket of soapy water.

During the summer, butternut squash plants profit from regular watering and fertilizing. Make sure the vines get at least an inch of water per week. Add mulch around the plants so that the fruit do not have direct contact with the soil. This will keep them dry and help prevent rotting, plus mulch helps retain water in the soil. You can also place small boards, flat stones, or bricks under the fruit to keep them off the ground.

Butternut Squash Care

Butternut squash seeds in seed tray with soil closeup

The Spruce / Steven Merkel

Butternut squash sprout with clump of soil on wooden plank

The Spruce / Steven Merkel

Small butternut squash plants in black pots

The Spruce / Steven Merkel

Butternut squash vegetables laying in bed of straw

The Spruce / Steven Merkel

Wooden crate filled with butternut squash vegetables

The Spruce / Steven Merkel


Butternut squash needs full sun, ideally 6 hours per day. More time in the sun is fine, provided the plants are not overheated.


The soil should be rich in organic material, and it must drain well. It can be slightly acidic to neutral, with a pH of 5.5 to 7.0.


Seedlings must not be allowed to dry out. As the summer progresses and the vines get bigger, your plants will need even more water. During hot, dry weather, leaves may wilt on a daily basis but will revive as the day cools. If leaves are wilted in the morning, water the plants right away. The plants need at least 1 inch of water per week.


Butternut squash is a heavy feeder. Start with rich soil, and side dress with organic compost or aged manure in the middle of the growing season. In addition, apply a compost tea or liquid fertilizer at two- to three-week intervals.

Temperature and Humidity

Squash are cold-sensitive and will not germinate unless the soil is at least 70 degrees Fahrenheit. These plants love the sun, but they can overheat. During the hot days of summer, it's normal for the leaves to wilt in the afternoon, then revive after the sun goes down. If your plants are not reviving, try giving them some afternoon shade.

Winter Squash vs. Summer Squash

A "winter squash" is defined as a kind of squash that has a hard enough skin that it preserves well if stored in a cool place. Thus, if you were to harvest one in October, it would keep until at least December (winter) if stored in a suitable place, such as un unheated basement or root cellar.

Butternut squash is just one of several winter squashes that are commonly grown. Another popular winter squash is Hubbard squash (Cucurbita maxima), which has a gray, bumpy exterior.

In contrast to winter squashes, there are also summer squashes, such as zucchini squash (Cucurbita pepo var. cylindrica). Summer squashes have a soft skin that is edible and perish quickly.


Use the color of the fruits to determine when to harvest them. As summer winds down, their skin will begin to turn light beige. They are ready to harvest when that beige color becomes deeper; the skin will often have bronze highlights (and no green streaks) in it when the fruit is ripe. Harvest fruit before frost, but make sure the fruit is fully mature so that it will last longer when stored. Three other indicators will help you determine maturity:

  • Check the stem where it meets the fruit; it turns a brownish color (as if drying out) at maturity.
  • The skin should have a dull appearance (no shine).
  • Poke the skin with your fingernail. If it leaves a mark, it's immature. Let it continue to mature. A fully mature fruit's skin will be too hard to pierce.

Once you harvest the squash, cure it for 1 to 2 weeks before storing. Keep it outside in a warm, sunny space. Once it's cured, move it inside to a dry, cool location with temperature at about 55 degrees.

How to Grow Butternut Squash From Seed

Most gardeners purchase butternut squash seed packets (available at grocery stores, hardware stores, online, and from seed catalogs). Once you have the seeds, you can start them indoors to get a jump on the season, or you can wait until danger of frost has passed and direct-sow outdoors. Direct seeding in the garden is easier, but starting seeds indoors can be helpful to those in areas with short summers.

To start seeds indoors, plant them about three weeks before the last frost in spring. Fill 3-inch biodegradable pots with potting soil, and plant two seeds in each pot. Water, and place the pots in a sunny window. Do not let the soil dry out completely. If both seeds in a pot germinate, select the healthiest seedling as the one to keep and pinch out the other.

When the plant has two sets of true leaves, begin the hardening off process. On warm days, set the pots outdoors in partial sun for a few hours at a time. Bring them back indoors at night. Gradually increase the number of hours that they stay out, as well as the sun exposure. This process helps them adjust to the transition from an indoor environment to an outdoor environment. Plant the biodegradable pots in the ground once the soil temperature is at least 65 degrees Fahrenheit and all threat of frost has passed.

If you choose to direct seed, simply skip to the step where you create hills and plant four or five seeds in each hill, thinning them out later.