How to Grow Pumpkin

Pumpkin seedlingPumpkins are a warm-season annual that require from 90 to 120 frost-free days to reach harvest. Sow pumpkins in the garden in spring when all danger of frost has passed and the soil temperature has reached 65°F and night air temperatures are above 55°F. In cool-summer regions grow smaller varieties. Pumpkins can be started indoors 2 to 3 weeks before the average last frost date in spring; transplant them into the garden 2 to 3 weeks after the last frost.

Description. Pumpkins are tender squash-like annuals with smooth rinds scored with vertical grooves. Fruits can range in size from a few ounces to hundreds of pounds and in color from deep orange to white. Large, green leaves grow on branching vines that can reach 20 feet long. Large male and female flowers grow on the same vine. The name pumpkin is also given to other hard, orange squashes and gourds.

Yield. Plant 1 to 2 pumpkin plants per household member.

Site. Plant pumpkins in full sun; pumpkins will tolerate partial shade. Pumpkins grow best in loose, well-worked, well-drained soil rich in organic matter. Pumpkins prefer a soil pH of 6.0 to 7.5. Add aged compost to planting beds in advance of sowing. Pumpkins require ample room for growing or train them up a fence or trellis. Bush varieties require less space than vining varieties.

Planting time. Pumpkins are a warm-season annual that require from 90 to 120 frost-free days to reach harvest. Sow pumpkins in the garden in spring 2 to 3 weeks after the average last frost date when the soil temperature has reached 65°F and night air temperatures are above 55°F. Pumpkins can be started indoors 2 to 3 weeks before the average last frost date in spring for transplanting into the garden 2 to 3 weeks after the last frost. In cool-summer regions grow smaller, quick-maturing varieties. Pumpkins are sensitive to cold soil and frost. In warm-winter regions, plant pumpkins in winter for harvest in mid to late spring. Pumpkins grow best in temperatures from 50° to 90°F.

Planting and spacing. Sow pumpkin seeds 1 inch deep and 3 to 4 inches apart. Plant pumpkins raised mounds 8 to 12 inches high and 12 to 18 inches across or in inverted hills made by removing an inch of soil from a circle 12 to 18 inches in diameter using the soil to build up a rim around the circle. Space hills 6 to 8 feet apart. Sow 6 to 8 seeds in each hill, and thin to the 2 or 3 strongest seedlings. When plants have 4 to 6 true leaves, thin to only one or two plants per hill. Cut off thinned seedlings at soil level to avoid disturbing the roots of the remaining plant.

Water and feeding. Pumpkins require regular, even water to keep vines and fruiting growing without interruption. Do not let the soil dry out. Add aged compost to the planting are before planting. Side dress pumpkins with compost or manure tea every two weeks during the growing season.

Companion plants. Corn. Avoid planting pumpkins with potatoes or squash.

Care. Keep the planting area weed free. The first flowers to appear will likely be male flowers which do not bear fruit. Female flowers will bear an immature pumpkin beneath the blossom; these flowers must be pollinated by the male flowers for mature fruits to develop. Allow just 2 or 3 fruits to mature on each plant. Set tripods or trellises in place at planting. Set developing fruits on wooden planks so that they do not develop rot sitting on wet soil.

Container growing. Pumpkins require a great amount of space and so are not good candidates for container growing. Choose a space-saving variety for containers.

Pests. Pumpkins can be attacked by squash borers and cucumber beetles. Hand pick or hose away beetles. A small hole in the stem or unexplained wilting may indicate the presence of borers. Slit the stem, remove the borers, and dispose of them. Cover the slit stem with soil to encourage root development from that point.

Squash borers or bacterial wilt can cause squash plants to suddenly wilt and die just as they begin to produce. Bacterial wilt can be spread to squash by cucumber beetles; handpick and destroy cucumber beetles.

Diseases. Pumpkins are susceptible to bacterial wilt, mosaic virus, and mildew. Plant disease-resistant varieties. Keep the garden clean and free of debris where diseases and pests may harbor. Water at the base of plants to keep water off the foliage, and do not handle plants when they are wet to avoid the spread of fungal spores. Remove and destroy infected plants before they spread disease to healthy plants.

Bacterial wilt is spread by cucumber beetles. Bacterial wilt will cause pumpkin plants to suddenly wilt and die just as they start to produce pumpkins. Control the beetles to control the spread of disease.

Mosaic virus can cause squash plants to become mottled yellow and stunted. Mosaic virus is spread by aphids. Control aphids and remove affected plants.

Powdery mildew, a fungus disease, will cause leaves to turn a gray-white color late in the season. Proper spacing and increased air circulation will help reduce this problem.

Harvest. Pumpkins will be ready for harvest 95 to 120 days after sowing. Pick pumpkins when they are deeply colored, deep orange or golden white and stems and vines have dried and turned brown. The rind should be hard, not easily penetrated by a finger nail. Use a pruning shears to cut the vine; leave 2 to 4 inches of stem attached to the pumpkin so that it does not readily dry out. Harvest before the first freeze or pumpkins will turn soft.

Varieties. Grow small pumpkins for cooking; grow intermediate and large sizes for cooking and for making jack-o’-lanterns; grow extra-large pumpkins for exhibition.

Extra-large (50 to 100 pounds): Atlantic Giant (125 days); Big Max (120 days); Big Moon (120 days); Mammoth King (120 days); Prizewinner (120 days); The Great Pumpkin (120 days).

Large (15 to 25 pounds, 100 days): Aspen (93 days); Connecticut Field (120 days); Ghost Rider (115 days); Half Moon (115 days); Howden (115 days); Pankow’s Field (120 days); Pro Gold (95 days); Tallman (110 days); Wizard (115 days).

Intermediate (8 to 15 pounds): Autumn Gold (90 days); Big Autumn (100 days); Jack O’Lantern (115 days); Oz (105 days); Small Sugar Pie (110 days); Tom Fox (110 days); Trick or Treat (105 days).

Small (4 to 6 pounds): Bush Spirit (100 days); Frosty (95 days).

Others: Baby Bear (105 days); Baby Boo (95 days); Buckskin (110 days); Cushaw, Green Striped (110 days); Gremlin (100 days); Japanese Pumpkin (110 days); Jarrahdale (110 days); Lady Godiva (110 days); Little Gem (110 days); Little Lantern (100 days); Long Cheese (120 days); Lumina (110 days); Munchkin (110 days); Rouge D’Etampes (95-160 days); Sweetie Pie (110 days).

Storing and preserving. Cure pumpkins in direct sun at 75° to 80°F for 2 weeks; then store at 50° to 55°F, in a dry, well-ventilated place for 3 to 6 months. Do not refrigerate. Pumpkins in storage will shrink as much as 20 percent in weight but are still suitable for cooking. Pumpkin can be pureed and frozen for up to 6 months. Pumpkin also can be frozen or canned.

Common name. Pumpkin

Botanical name. Cucurbita maxima, Cucurbita moschata, Cucurbita pepo

Origin. Topical America