Start seeds indoors
Press seeds 1 inch deep, firm soil over them, and keep the top inch moist until sprouts show — do not let the seedbed crust over. Seedlings emerge in 5–10 days in warm soil.
A vining winter squash that stores for months and delivers dense, sweet orange flesh from a single long season of warmth.
Cucurbita moschata · also called butternut pumpkin, gramma squash
Windows are counted from the average date of your last spring frost.
Butternut squash produces reliably heavy yields from a small number of plants and keeps in a cool room for up to 6 months without any special equipment. Its thick skin resists the powdery mildew that shortens the season of many other squash types.
A little history. Native to Mesoamerica and among the most mildew-tolerant species in its genus; the tan skin cures to a hard rind that seals the flesh and extends storage far beyond summer squash.
Press seeds 1 inch deep, firm soil over them, and keep the top inch moist until sprouts show — do not let the seedbed crust over. Seedlings emerge in 5–10 days in warm soil.
Sow seeds 1 inch (25 mm) deep.
Beds strongly preferred — vines reach 10–15 feet; containers require a minimum 15-gallon volume and a trellis. In containers: 15-gallon pot with a sturdy trellis to support fruit. Space plants 36 inches (90 cm) apart.
Deep soak twice a week; increase to every other day during fruit swell in hot weather. Water when the top 2 inches of soil feel dry, or leaves show slight wilting in the morning. Aim for about 1–2 inches per week including rain.
Side-dress (scatter fertilizer along the row and water in) once vines reach 12 inches, then again at first flower. What to use: balanced 5–5-5 organic at vine stage; switch to a lower-nitrogen, higher-potassium feed at flowering.
Pinch off the growing tip of each main vine once 2–3 fruits have set to direct energy into those fruits; remove any secondary fruits that form after that point.
It's ready when skin turns fully tan-beige with no green streaking; the thumbnail cannot dent the rind; the stem has dried and corked over; the blossom end feels firm. Cut the stem with a sharp knife or pruners, leaving at least 2 inches of stem attached to the fruit — never snap or twist the stem off, as a broken stem shortens storage life significantly.
Cure at 80–85 °F (27–29 °C) for 10–14 days to harden the rind, then store at 50–55 °F (10–13 °C) in a dry, well-ventilated spot; keeps up to 6 months. Do not refrigerate uncured fruit.
Sweet Corn
In the Three Sisters planting, corn lends the vertical stalk while the squash's broad leaves sprawl across the ground, shading out weeds and slowing moisture loss from the soil around the corn roots. Give the corn a 3-4 week head start so the vines do not swamp young stalks.
Pole Bean
Pole beans bank nitrogen in root nodules, but most of it is released only as those roots break down, so the benefit lands on next season's crop in this bed rather than on this year's vines. The two also share space well when beans climb corn or a trellis above the sprawl.
Nasturtium
Aphids and squash bugs often settle on nasturtium first, which can pull early pressure off young squash. It only helps if you check the nasturtiums weekly and pull or wash off the colonies rather than letting them build.
Borage
Squash sets fruit only when bees carry pollen from male to female flowers, and borage's nectar-heavy blue flowers draw in bumblebees and honeybees all season. Plant a couple of plants at the bed edge, well clear of the running vines.
Radish
Radishes sown alongside squash hills can absorb some early cucumber beetle and flea beetle feeding, and they are pulled within a month, long before the vines need the space. Treat them as a bonus, not a substitute for row cover on seedlings.
Potato
Both are hungry crops that compete for water and food in the same top foot of soil, and digging potatoes in late summer means forking through the shallow squash roots and running vines. Keep them in separate beds.
Fennel
Fennel roots release substances that stunt most garden vegetables, squash included, so it does not belong in or beside the squash bed. Grown in its own corner well away from the vines, its flat flower heads feed hoverflies and tiny parasitic wasps and earn their place.
Give the squash family 2 years away from this spot before any of its relatives return.
The pea and bean family, the carrot family or the onion family thrive in this ground next season.
Butternut is a heavy feeder that leaves depleted, root-broken soil and no nitrogen behind, so replace what it took with compost. Keep the squash family out of this bed for 2 years, then follow with legumes such as peas or beans, umbellifers like carrots, or an allium crop such as onions.