University of California
UC Master Gardener Program of Sonoma County
Pumpkins
Pumpkins conjure up a nostalgic feeling for simpler days of growing crops on the farm and prompt families to tromp through acres of orange orbs in search of the perfect pumpkin. Home gardeners are one step ahead by growing their own miniatures, giants, blue, white, green, edible, and ornamental varieties to satisfy every whim.
Garden Planning
- Pumpkins take up a lot of space. It is important to reserve an area for vines to spread when you plan your summer garden.
- Many gardeners plant pumpkins in beds where spring crops such as peas or lettuce have ended.
- Check seed packets for growth details. Some vines trail to more than 20 feet with many vines that produce multiple pumpkins per vine.
- Mini-pumpkin vines can be trained on a wire fence or tomato cage. Larger fruit grown on a trellis may require supports; slings made out of old t-shirts or nylon stockings work well.
Making Choices
- Pumpkins of all sizes are suitable for carving—depending on an individual’s artistic expression—and for cooking and baking. (See: “Two Cautions” below)
- ‘Big Max’, 50-100 pounds, is favored for creative carving.
- ‘Cinderella’ (‘Rouge d'Etampes’) is flattened, deep red-orange, 10 in. in diameter, 20-25 pounds, favored for cooking and baking.
- ‘Jack-be-Little’ is a miniature, decorative fruit just 3 in. across and 2 in. high.
- ‘Small Sugar’, 5-6 pounds, is the classic choice for pumpkin pies.
- ‘Baby Bear’ and ‘Bushkin’ are bush pumpkins suitable for growing in a container with compact vines only a few feet long and small-medium sized fruits. Their sweet flesh is prized for baking.
- ‘Jack O’Lantern’ and ‘Autumn Gold’ are popular intermediate sizes good for carving or cooking.
- The mammoth types such as ‘Dill’s Atlantic Giant’ produce 400-500 pound pumpkins or double that. They are not true pumpkins, but a related species of winter squash.
Two Cautions
- Do not use pulp from carved jack-o-lanterns in any cooking or baking. Bacteria grows easily and fast when pumpkins are cut open and pulp is exposed to air.
- USDA instructs us not to can mashed or puréed pumpkin or pumpkin butter. Pumpkin is a low-acid food capable of supporting the growth of the bacteria that causes botulism.
Planting and Care
- Amend soil with compost and apply a slow-release organic fertilizer a few weeks before planting. If using rotted manure with straw, apply nitrogen fertilizer as well.
- Sow seeds directly in the ground, following directions on seed packets, in moist, warm soil after the last April frost date but no later than June for harvest by October. Most varieties take 100-120 days to mature, or select an early 90-day variety if your area has a short growing season.
- Plant in hills, 6 seeds in a circle about 10 in. in diameter; then, thin to 3 plants with hills 6-10 ft. or farther apart, depending on varieties.
- Water early in the day so leaves dry before evening to prevent foliar wilt diseases. Drip irrigation is best throughout a wide area where roots spread.
- Allow soil surface to dry between waterings but maintain even moisture to 12 in. deep.
- Encourage production of 1 or more large pumpkins by pruning off smaller ones. Vines will then send energy to remaining fruits. Wait, however, until undesired fruits reach 4-6 in. in size to allow time for plants to self-prune, then nurture the remaining fruits.
- Scratch a name into the rind before the shell hardens (usually in late August or early September) if you want to personalize a jack-o-lantern. The inscription will callus over and become more distinguishable as the pumpkin matures.
Harvesting and Storing
- Wait for pumpkins to fully ripen before harvesting. Rinds will be hard and stems will turn brown. They generally become even-colored although the side touching the soil may have a lighter hue.
- Use a sharp knife or pruners to harvest, leaving 4-5 in. of stem attached, but do not lift by the stem to avoid breaking it. Without the stem, pumpkins will not store well.
- Move the fruit away from wet soil to a dry, warm area for 1-2 weeks to cure before storage.
- Store pumpkins in a dry, fairly cool area, ideally at 50-60 degrees for up to 2 months.
Additional Information
- Sonoma County Master Gardener Vegetable Planting Summary
- https://sonomamg.ucanr.edu/Food_Gardening_with_Less_Water/
- http://ipm.ucanr.edu/home-and-landscape/pumpkins/cultural-tips/
- http://ipm.ucanr.edu/home-and-landscape/pumpkins/index.html
February 2022