Pumpkins are a member of the cucurbit family (Cucurbitaceae), along with cantaloupe, cucumbers, squash, watermelon, and gourds. Native to the Americas, the various types of pumpkin break down into four species—Cucurbita moschata, Cucurbita mixta, Cucurbita pepo, and Cucurbita maxima . Since pumpkins share many traits with squash, there may be some overlap in identification in various regions of the United States. In general, pumpkins have coarser flesh and a stronger flavor than squash, though they can be easily cross-pollinated with their own varieties and with squash, resulting in many different colors, sizes, and shapes.
Evidence of pumpkin consumption dates as far back as 7,000 to 13,000 B.C. to cliff dwelling Native Americans in the southwestern United States and in northern areas of South America such as Mexico and Peru. These tribes cultivated pumpkins before Europeans arrived and likely passed them on to the rest of the world, spreading to East Asia in the sixteenth or seventeenth centuries.
References: Agricultural Marketing Resource Center, PennState Extension, University of Georgia Extension, University of Florida/IFAS Extension.
TYPES, VARIETIES & CUTS
Pumpkins can be broken down into four usage and size categories: giant, Jack O’ Lantern, pie, and ornamental. Giant pumpkins range from 25 to as large as 1,000 pounds. Jack O’ Lanterns are usually ribbed fruits with smooth to bumpy orange skin ranging from about 10 to 25 pounds. These are typically used for carving during Halloween; they are also used to make pies and other dishes, for stock feed, and for their edible seeds. Pie pumpkins—named for their most common use—are generally smaller and sweeter with smooth, firm, bright flesh ranging from about 5 to 10 pounds. Ornamental pumpkins are miniature, usually weighing less than a pound, and used primarily for decoration.
While pumpkins are typically thought of as being orange with smooth skin, varieties range from white or orange to green with either a bumpy or smooth texture, and from solid colored to striped.
References: Agricultural Marketing Resource Center, University of Florida/IFAS Extension, University of Georgia Extension.
PESTS & DISEASE
A host of insects can play havoc with pumpkin development and growth. Many favor excess moisture and cool conditions, causing damage to varying parts of the fruit: beetles affect stems, leaves, and flowers; thrips, aphids and melonworms go after leaves; cutworms attack below the surface and pickleworms bore into the fruit. Other pests include grasshoppers, leaf hoppers, leaf miners, nematodes, root maggots, seed corn maggots, spider mites, squash bugs, squash vine borers, stink bugs, whiteflies, and wireworms.
Fungus-based diseases can be carried by wind, rain, or infected seeds, soil, or machinery. Excess or extended periods of rain will increase the likelihood of alternaria leaf spot, anthracnose, gummy stem blight, target spot, belly rot, and crown rot. Each of these diseases can cause spots, lesions, or cracks in the fruit.
Powdery and downy mildew are common threats; the former is caused by an airborne fungus that thrives in dry, hot conditions. Symptoms include white or brown-tinged growths on leaves and can also attack stems. Downy mildew is also caused by airborne fungi, but thrives in wet, cool weather and will cause yellow to brownish discolorations on the surface of leaves and molding underneath. Some new cultivars are resistant to powdery mildew.
Angular leaf spot and fruit blotch are bacteria-based diseases, and spread by infected seeds or debris left after harvest. Both cause spots and lesions on leaf margins and surfaces. Angular leaf spot worsens in wet, warm conditions. Mosaic is caused by any one of several viruses, spread by aphids. Symptoms include mottling and distortion or appear as chemically-induced damage.
Other diseases include bacterial wilt, fusarium crown, phytophthora blight, mildew, and various types of blight.
References: PennState Extension, Purdue University Extension, University of Georgia Extension, University of Illinois Extension
CULTIVATION, STORAGE & PACKAGING
Pumpkins require full-sun conditions with air temperatures of at least 65 to 75°F. Temperatures below 50 or above 95°F will slow growth. Soil temperatures should range from at least 70 to 80°F for proper germination. Soil texture must be coarse to medium to retain water and should be well-drained and aerated with a 5.8 to 6.6 pH level. Pumpkins will grow in sandy soil provided irrigation is adequate as plants require constant moisture, particularly during blossoming and fruit set. Crop rotation with noncucurbits is ideal for disease and pest control.
Pumpkins may be field-seeded or transplanted and require approximately four months for full maturity, depending on the variety. Seeding requires from two to four pounds of seed per acre. Seeds should be covered to about one inch or slightly deeper in light soils. Spacing depends on the type of plant (bush, semi-bush/vining, or vining) for anywhere from 600 to 3,000 plants per acre. Plants require from 5 to 12 feet between rows with 30 to 40 inches between plants. The large-leaved, spreading plants become competitive with weeds once they begin to mature.
Pumpkins develop both male and female flowers on the same plant and require honey bees for pollination. Requirements are about one commercial hive for each acre as plants need from 7 to 10 visits per flower and native bees are generally not enough to pollinate an entire crop. Particular care must be used when applying any chemicals to the crop to avoid harming bees. Plants are pollinated at different times, requiring multiple harvests throughout the season.
As plants grow and develop fruit, pruning back to only two pumpkins per plant produces larger fruit. Mature fruit must be harvested before a hard freeze, though a light frost can be tolerated. Fruit color is often the best indicator of maturity.
Pumpkins are hand-harvested and prone to damage from rough handling. Cuts and bruises are entry points for pests and disease though very small cuts will heal during curing. Pumpkins are harvested by cutting from the vine, leaving an inch or more of the vine attached to the fruit. Pumpkins are usually graded in the field and loaded into trailers or bins lined with straw or some other cushioning material to prevent injury.
Fruit is cured at 70 to 85% relative humidity at 80 to 85°F for 10 to 20 days. Ideal post-curing storage is in a cool, dry environment between 50 to 60°F with good air circulation. Pumpkins are best stored in a single layer rather than stacked to prevent decay. Properly stored pumpkins will keep for two to three months.
References: PennState Extension, University of Georgia Extension, University of Florida/IFAS Extension.