key growing information

Winter Squash Growing Information: How to Plant, Grow & Harvest

How to grow winter squash: soil, starting transplants and spacing, plastic mulch and row covers, direct sowing in warm soil, diseases, pests, frost, harvest, curing, storage and seeding rates by type.

By Hensley’s Seed Co. September 3, 2026

Winter Squash - Key Growing Information

Baskets of winter squash, including delicata, kabocha, butternut, spaghetti, acorn, and blue hubbard.

SCIENTIFIC NAME:

Cucurbita spp.

CULTURE:

Fertile, well-drained soil gives the best results.

FROM TRANSPLANTS:

Plant 2–3 seeds in each 2" pot or plug trays 3 weeks before planting out, thinning to 1–2 plants per cell with scissors. Transplant once frost danger has passed and the weather is warm and settled. Space bush and small-fruited types 18" apart with 4–5' between rows, and large-fruited types 24–36" apart with 6–12' between rows. Be careful not to disturb the roots. Plastic mulch and fabric row covers help plants get established, cut weed pressure and keep insects off.

DIRECT SEEDING:

Sow in late spring once frost danger has passed and the soil is warm: at least 62°F (17°C) for treated seed and 70°F (21°C) for untreated seed, since seed rots in cool soil, especially when it's also wet. Plant 1–2 seeds ½–1" deep every 12" (24–36" for large-fruited types), thinning to one plant per spot, with rows 6' apart or 12' for bigger fruit.

DISEASES:

Cucumber beetles spread bacterial wilt and need to be controlled. Gummy stem blight (black rot) causes sunken black spots on stored fruit and tan, scabby patches on butternuts in the field. Downy mildew can show up in damp weather, and powdery mildew in hot or cool spells or dry periods. Ask your local Cooperative Extension office about fungicide options, and plant in well-drained soil to avoid Phytophthora.

SPRING COLD PROTECTION:

Floating row covers of AG-19, DuraSpun-55 or heavier give about 4°F of frost protection and add warmth for stronger growth and an earlier harvest.

INSECT PESTS:

Protect young plants with floating row covers or kaolin clay. Cucumber beetles, squash bugs and vine borers can all be a problem; pyrethrin gives some control. Look for squash bug eggs under the leaves and crush them, and keep field edges mowed. For vine borers, cut them out of the vine and mound soil over the wound. Clear debris in fall and plow in spring to bury pupae. Moschata types have solid vines that borers usually leave alone.

FALL FROST:

Frost kills the leaves, which can make harvest easier, but temperatures below 28°F (-2°C) can also damage fruit, causing spots and poor storage. Mature fruit usually takes one light frost, sometimes two or three, without much harm, and sprinkler irrigation helps protect fruit from moderate frost.

HARVEST:

Before a hard frost, once the stem is drying and the skin hardening, cut the stem about 1" from the fruit. Handle gently, as the fruit bruises easily.

POST HARVEST:

Cure in the field for about 5–7 days in the sun to dry and toughen the skins, covering them at night if frost threatens. Dark green types sunburn more easily and may need to cure out of direct sun. To cure indoors, hold squash at 80–90°F (27–32°C) with airflow for 3–5 days.

STORAGE:

Store at 55–60°F (13–16°C) and 50–75% relative humidity with good airflow. Repeated exposure below 50°F (10°C) adds up to chilling injury and shortens storage life.

DAYS TO MATURITY:

Counted from direct sowing; take off about 14 days for transplants.

AVG. DIRECT SEEDING RATES:

At 2 seeds per foot in 6' rows: Group 1 (Hubbard, Kuri), about 50' per oz., 850' per lb., 8½ lb. per acre. Group 2 (Buttercup, Kabocha, Spaghetti), about 75' per oz., 1,250' per lb., 5¾ lb. per acre. Group 3 (Butternut, Acorn), about 155' per oz., 2,500' per lb., 3 lb. per acre. Group 4 (Delicata, Sweet Dumpling), about 225' per oz., 3,750' per lb., 2 lb. per acre.

SEED SPECS:

See each variety.

PACKET:

30 seeds.