How to Grow Butternut Squash
Butternut Squash At a Glance
Difficulty
Easy
Category
Vegetable
Sun Exposure
Full Sun
Frost Tolerance
Frost Tender
Cold Hardiness
Survives to 4°C
Plant Family
Cucurbitaceae
Growing Season
Warm Season
Plant Lifecycle
Annual
How to Start It
★ Recommended for beginners
Sow 1 to 2 weeks after your last spring frost, once the soil feels warm. Push 2 to 3 seeds 2.5 cm deep into a small mound of compost-rich soil, and give each mound at least 90 cm of room. They sprout in 7 to 14 days: keep the strongest seedling and snip off the others at soil level.
Butternut is the best keeper of the winter squashes: its hard, tan skin lets it last for months on a shelf. It needs a long, warm summer, so in a short-season area an indoor start or your warmest, sunniest corner makes the difference. Its solid stems also stand up better than most squash to the grubs that tunnel into squash vines.
When To Start
Butternut Squash needs warmth. Wait until your last frost has passed and the soil has warmed before sowing.
We do not have exact sowing dates for this one yet.
When should you plant Butternut Squash?
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Your Butternut Squash Planting Window
Start planting
May 15, 2026
Last chance
Sep 10, 2026
Your Butternut Squash Calendar
Set your location to turn these into exact dates and reminders.
Sow butternut squash outdoors now that the soil is warm
1 week after your last frost
Optional: start butternut indoors if your summers are short
3 weeks before your last frost· optional
Cut butternut when the skin is all tan and the stem is corky
About 105 days after you plant it
Did you water your butternut squash seedlings today? Keep the top of the soil damp until they are up and growing.
About 1 days after you plant it
Hello to your butternut squash! Water deeply at the base and let the vines roam.
About 49 days after you plant it
Your butternut is filling out. Wait until the skin is fully tan and hard and the stem is corky, before frost.
About 84 days after you plant it
Picking time may be here: check your butternut squash.
About 105 days after you plant it
Step 1
Prepare Your Space
2.5 cm
Seeding Depth
90 cm
Plant Spacing
180 cm
Row Spacing
Vertical Growing
Yes: Trellis (support the fruit).
Succession Planting
No.
Good Companions
Bad Companions
Step 2
Planting & Sprouting
Expect sprouts in 7–14 days
Growing Tips
- 1Plant butternut in your sunniest spot, with at least 8 hours of sun a day.
- 2Mix plenty of compost into the planting mound, since squash is a hungry plant.
- 3Water deeply at the base about once a week, more in hot spells, and keep the leaves dry to slow powdery mildew (a white dust on the leaves).
- 4Feed with worm castings or compost tea when the vines start to run and again when the flowers appear.
- 5In late summer, pinch off the vine tips and any new flowers so the plant puts its energy into ripening the squash it already has.
- 6Look under the leaves for squash bugs and their shiny bronze eggs, pick them off by hand, and slip a board or some straw under each squash to keep it off damp soil.
Step 3
Growth & Maturity
~105
Days to Maturity
40 cm
Mature Height
300 cm
Mature Width
Pests to Watch For
Diseases to Watch For
Step 4
Harvesting
Harvest Window
21 days
When to Pick
Cut when fully tan, rind hard, stem corky, before frost
How to Harvest
- 1Butternut is ready when the skin is an even tan all over, too hard to dent with a fingernail, and the stem has turned dry and corky.
- 2Cut it off with pruners, leaving about 5 cm of stem, and never carry it by the stem.
- 3Bring every squash in before the first fall frost.
- 4Cure them (let the skin harden) in a warm, dry room for 1 to 2 weeks, which also makes the flesh sweeter.
- 5Store them in a cool, dry place, where they keep for several months.
Step 5
Saving Seeds
How to Save Seeds
Butternut crosses with other squash of its own kind, such as other butternuts and some pie and cheese pumpkins, but not with zucchini or acorn squash. If another squash of its kind flowers within about 800 m, tape a female flower (the one with a tiny squash behind it) shut the evening before it opens, brush it the next morning with pollen from a male butternut flower, and tape it shut again. Hybrid F1 seeds will not grow true, so save only from a variety that is not a hybrid. Let the chosen squash sit indoors for 3 to 4 weeks after harvest, then scoop out the seeds, rinse off the pulp and dry them on a plate for 1 to 2 weeks. Store them in a labelled envelope somewhere cool, dark and dry, where they keep about 5 years.
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