key growing information

Growing Buttercup Squash: How to Sow, Care for & Harvest

How to grow buttercup squash: transplants or direct sowing, row and in-row spacing, pest and disease prevention, curing, storage and when it tastes best.

By Hensley’s Seed Co. September 3, 2026

Buttercup Winter Squash - Key Growing Information

Buttercup winter squash fruits; this variety is 'Bon Bon.'

SCIENTIFIC NAME:

Cucurbita maxima

CULTURE:

Rich soil that drains freely, with a pH in the 6.0–6.8 range, gives the best results. Plastic mulch plus lightweight row covers (AG-19 weight) help young plants get going and keep insects off seedlings. Take the covers off when flowering starts so bees can reach the blossoms; misshapen or aborted fruit is often a sign that pollination fell short.

TRANSPLANTING:

About 3 weeks before planting out, sow 2–3 seeds in each 2" pot or cell of a plug flat . Snip off the extras with scissors so one seedling remains per cell. Spend 4–7 days hardening the plants off, then set them out after the last frost at the spacing listed for your variety. Squash roots resent disturbance, so move the seedlings gently.

DIRECT SEEDING:

Plant seeds 1/2–1" deep, two at each planting spot, using the spacing that fits the variety's vine length. Once the seedlings are growing well, remove the weaker one at each spot.

PLANT SPACING:

Between rows, allow about 6' for bush and short-vine types and about 12' for long-vine types. Within the row, space by fruit size: roughly 18–24" for small, 24–36" for medium and 36–48" for large fruit.

DISEASES:

Powdery mildew, downy mildew, bacterial wilt and Phytophthora are the main squash-family diseases. Good drainage, open airflow, controlling insects and rotating crops prevent most problems. For specific treatment options, contact your county Cooperative Extension office.

INSECT PESTS:

Expect cucumber beetles, squash bugs and squash vine borers. Floating row cover shields young plants. Crush clusters of squash bug eggs on leaf undersides by hand. If a borer gets in, slit the stem to remove it and mound soil over the damaged section. Mowing field edges, clearing crop debris in fall and turning the soil in spring to bury overwintering pupae all cut down on pests. Pyrethrin sprays can help somewhat.

HARVEST:

Fruit typically matures 50–55 days after it sets; bring it in before a hard frost. Cut the stem rather than pulling, and handle fruit gently. Cure it in the sun for 5–7 days, or indoors at 80–85°F/27–29°C with plenty of air movement.

STORAGE:

Keep cured squash at 50–60°F/10–15°C and 50–70% relative humidity with good airflow. Temperatures below 50°F/10°C, especially repeatedly, can cause chilling injury. How long squash keeps, and when it eats best, depends on the type: buttercups sweeten after a few weeks in storage and hold for up to about 4 months.

DAYS TO MATURITY:

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

AVG. DIRECT SEEDING RATES:

(Based on 2 seeds per foot in rows 6' apart.) About 1 oz per 75', 1 lb per 1,250', or 5¾ lb per acre.

SEED SPECS:

Varies by variety; see each product page.

PACKET:

30 seeds per packet.