Whether or not your future holds your favorite butternut squash meals hinges on your knowing when to plant butternut squash. While that may sound dramatic, the timing for sowing seeds and transplanting squash plants makes a difference. Butternut squash is a favorite winter squash variety, and it can be grown in most climates.

If you’ve grown other winter squash types, such as Delicata, pumpkins, Hubbard, acorn squash, or spaghetti squash, you may already be familiar with the importance of getting the timing right. For anyone new to growing winter squash and everyone who needs a refresher (honestly, who doesn’t?), this article will cover the length of the growing season, how to determine your planting date, two ways to plant butternuts, some varieties to know, and growing and harvest tips.

Meet the butternut

I like to think of butternut squash as the squash the needs no introduction. This peach-colored, pear-shaped squash has a firm flesh and nutty flavor that lends itself to all kinds of winter comfort foods. You can even eat it raw, believe it or not.

This vegetable packs a nutritional punch, too, with 1/2 cup of butternut providing 50% of your recommended daily allowance of vitamin A. It’s also full of potassium, fiber, manganese, vitamin C, and antioxidants.

How long does it take to grow butternut squash?

To determine when to plant butternut squash, you first need to know how long it takes to grow. Days to maturity differ by variety, from 75 to 100 days. This is quite a range, so pay attention to the listed days to maturity when you choose your variety. A gardener in the northern reaches can grow a 75-day squash but probably not a 100-day squash.

The exact time it takes to grow butternut squash depends on the season’s growing conditions, too. If you have an unusually cool, wet season, your squash will not perform as well as in a warm season with adequate rainfall. The proper conditions allow the plant to produce both male and female flowers, and each is necessary for pollination. Pollinators visit the male flower first and transfer that pollen to the female flower. Males and females are only open for a short time each, so the pollinator visit needs to be timed just right. You can help this process by planting flowers and herbs that attract pollinators to your garden and by ensuring your butternut squash plants are in full sun, which will encourage them to produce more flowers.

Calculating the best planting date

Considering butternut squash is called a winter squash, it surprises some to know that it’s actually a warm-season crop. In calculating when to plant butternut squash, you need to know your last frost date in the spring and your first frost date in the fall. Look at the estimated days to maturity for the variety you selected. Count forward that many days from your average last-frost date, and count backwards that many days from your average first-frost date. This date range is when to plant butternut squash.

Two ways to plant butternut squash

Plants in the cucurbit family, including butternut squash, perform best when direct-seeded into the garden. They don’t like to have their roots disturbed, which can happen in the transplanting process. Of course, it is possible to plant butternut squash seed and transplants. You should understand the plusses and minuses to both.

When to plant butternut squash from seed

Refer back to your best planting dates, which you determined above. Sow butternut squash seeds when the soil is at least 65 degrees F and all danger of frost has passed. They will germinate best when the soil is 95 degrees F. Lay black plastic mulch on top of the planting bed to warm the soil, if needed. Expect germination in 5 to 10 days.

When to plant butternut squash from transplants

Transplanting butternut squash seedlings can take place at the same time as direct seeding, once the garden soil is warm enough. Because of transplant shock, the transplanted and the direct-seeded butternuts may mature at the same time.

You can reduce transplant shock in a few ways:

• Before transplanting, harden off the seedlings so they become acclimated to living outdoors. Water them less, and set them outside for an increasing period of time leading up to planting day.
• Don’t disturb the seedlings’ roots. Ideally, you’ll plant the transplants into the garden before they become root-bound.

The best varieties of butternut squash

What makes one variety of butternut squash better than another is subjective. You should look for one that will thrive in your climate, the days in your growing season, and the garden space you can devote to the vining plants. Choose a variety that tastes great, and also consider whether you want large or small butternuts, depending on how many people you’re feeding and how much space you have to store them.

Here are a few butternut squash varieties to know:

• ‘Waltham’ butternut: This is the classic butternut squash, coming in at about 6 pounds each. With 85 days to maturity, it’s a good choice for gardeners in many regions.
• ‘Honeynut’: Not a true butternut, ‘Honeynut’ is a very small, exceptionally sweet squash that was developed by crossing butternuts with buttercup squash. Some gardeners consider it more of a dessert squash.
• ‘Nutterbutter’: ‘Nutterbutter’ falls somewhere in between ‘Waltham’ and ‘Honeynut’, in terms of both size, weighing around 3 pounds, and flavor, which is sweet but not too sweet.
• ‘Burpee’s Butterbush’: One of the handful of heirloom varieties, these plants are compact and yield four or five squash each. Butterbush also grow quickly, with just 75 days to maturity.

General growing advice

Butternut squash is one of the few garden vegetables native to North America. They’re an ideal companion to corn and beans in the three sisters Indigenous planting tradition. The large leaves shade out weeds and cool the soil, while the beans fix nitrogen in the soil and the corn provides a structure for the beans to climb.

As a cucurbit, butternut squash is susceptible to many of the same pests and diseases as cucumbers, summer squashes, and other winter squash types.

One main disease is fungal: powdery mildew. This occurs with too much moisture, such as in areas with high humidity and a lot of rain. Plant butternut varieties resistant to the fungus, and space the plants so there’s good air circulation. (Learn more about how to control powdery mildew in this article.)

A number of pests affect butternut squash, too. (We can be thankful that, while they go after other winter squash, vine borers don’t usually bother butternuts. The borer can wipe out a plant in no time by burrowing into the stem.)

Here are a few pests to know:

• Cucumber beetles. Both the spotted cucumber beetle and the striped cucumber beetle snack on flowers and leaves. They also transmit the bacterial wilt pathogen. Row covers can protect young plants from pest damage, but you have to remove the row cover when the plants flower so they can be pollinated. Remove cucumber beetles by hand—this is easiest to do around dawn and dusk. Look on the underside of leaves for their eggs, as well. Try putting out a DIY cucumber beetle trap to catch the ones you’ve missed.
• Slugs and snails. These slimy mollusks live in damp areas, including the mulch that you probably use in your garden. They can damage plants and squash. Read this article for advice on how to control them.
• Squash bugs. Similar to cucumber beetles, squash bugs wreak havoc on butternut squash plants. Here are 8 ways to deal with squash bugs in the garden.

When to harvest

A few indicators can help you decide the best timing for your butternut squash harvest:

1. Keep track of when you plant butternut squash so you know when to harvest it. From your planting date, count out the number of days to maturity, and start checking the plants regularly from then on.
2. The vines start dying back, and the squash won’t receive any more nutrients from the plant. This is a good harvest-time indicator.
3. The squash rind is the color you’re expecting. It turns from green to orange as it matures. Depending on the variety, you may be looking for a light orange or a deeper brownish-orange.
4. The squash rind is hard. It can be dented but not punctured by your fingernail.
5. Frost is approaching. Be sure to bring in your squash before the frost. Immature squash isn’t ideal, but it’s better than no squash at all.

After harvest, cure the squash in a warm space, 80 to 85 degrees F with 80 to 85% humidity, for about a week. This hardens the skin, converts the starches to sugars, improves the flavor, and prepares the squash for long-term storage.

I only touched on the harvesting and curing process here. Read more about how to harvest and cure butternut squash in this article.

Splendid squash

Learning when to plant butternut squash isn’t difficult, it just takes some thought. Making this calculation, in fact, works for every crop in your garden. Learn about your growing season and the specific butternut squash variety you’ve chosen to determine the best planting dates in your garden. Remember that your gardening friends in another state and even those on the same block might have a different planting date, depending on these factors. Decide whether you’re planting by seed or transplant, be on the lookout for pests and diseases that could affect your plants, and you’ll have a great harvest before the frost arrives.

For more growing information on squash, please check out the following articles: 

• • How to cure winter squash
  • Growing spaghetti squash
  • When to harvest acorn squash
  • Cucuzza squash