University of Maryland Extension

Pumpkin - Giant Pumpkins

pumpkins lying in a field

  • Hardiness: Very tender warm-season annual. Frost will injure top growth; needs warm weather to grow.
  • Planting: Mix compost or well-rotted manure into the soil before planting and plant on a level part of your garden. For transplants, sow seed indoors in 3-inch diameter containers 3 weeks before planting time (about mid-May). Seed or transplants can be planted through black plastic to hasten maturity. After seedlings emerge, pinch out all but the strongest seedling. Handle transplants gently and disturb the root system as little as possible. A second crop can be planted between June 15 and July 1. This crop will be harvested around the time of the first frost. Full sun, requires direct light at least 6 hours/day; prefers 8 - 10 hours/day.
  • Days to maturity: Most pumpkins require more than 100 days to ripen.
  • Spacing: Plant 2 to 3 seeds every 3 ft. to 4 ft. apart in rows that are about 8 to 12 feet apart after all danger of frost has passed and the soil has warmed. Plant the seeds about ½” deep in the soil. Expect germination in 7 to 10 days. Thin seedlings by cutting excess plants with scissors rather than by pulling.
  • Fertilizer needs
  • Approximate yield: 10 to 20 pounds per 10-foot row.
  • Pumpkin Problems:

Growing and Care of Pumpkins

  • Pumpkin is a member of the genus Cucurbita and the family Curcurbitaceae, which also includes gourds. It is a winter squash recognized by its many creases running from the stem to the bottom on its thick-skinned shell. Pumpkin grows on long vines and comes in many varieties and colors, but we are most familiar with the orange variety.
  • It is harvested and eaten in the mature fruit stage, when its color has changed from green, usually well into the fall.
  • Like other winter squash, it can be stored intact for carving and eating later in the season. Some varieties are preferable for carving, some for making pies.
  • Pumpkin seeds can also be cleaned, dried, and salted for a healthful snack.
  • For smaller gardens, you can grow miniature pumpkins like ‘Jack Be Little’ or ‘Little Boo’, or you can grow them on a fence or trellis if you support the fruit as it grows.
  • Similar to other members of the squash family, pumpkins will produce male flowers for 1 to 2 weeks before their first female flowers. This is a normal growth habit and varies with cultivars. For a flower to develop into a fruit, pollen must be carried by bees from male flowers, on the same plant or on different plants, to the female flower (the one with the tiny squash). Poor fruit-set is common during rainy weather when bees are inactive. Avoid using pesticides during the bloom period because bees are easily poisoned, even using products labeled organic.

female squash flower
Female squash flowers

male and female squash flowers
Male flower on left; female on right

  • Watering – Water deeply and regularly at the base of each plant, especially during hot, dry weather and once the fruits start to form.
  • Weeding –Remove all young weed seedlings by hand or with a hoe and use a mulch around plants to keep weed seeds from germinating.

Tips on Growing Giant Pumpkins

  • Growing giant pumpkins is a lot of fun and can win you the ooohs and ahhhs of neighbors and prize money at county and state fairs!
  • Check seed catalogs and garden centers for cultivars known to produce large fruit- such as ‘Atlantic Giant’, ‘Big Max’, or ‘Big Moon’. It will take 4 months to get these pumpkin varieties to produce pumpkins in the 100+ pound range.
  • Mound up soil in the middle of the planting area and plant 3-5 pumpkin seeds about ½ in. deep. When the plants have their second set of leaves keep the strongest plant and cut the others at ground level with scissors. (Pulling them out could disturb the root system of your prize-winning pumpkin plant.)
  • Select one fruit – Monitor the growth of the baby pumpkin fruits on your plant. When they are 6-8 inches in diameter you should keep the largest and fastest growing fruit and remove the others. Remove all new blossoms that appear. Place a piece of cardboard under your giant pumpkin to prevent soil rots. You may want to try rolling the pumpkin very gently into a new position each week to keep it from becoming lopsided.
    • Prune vines – After selecting your one fruit, pinch back the ends of your vines to direct the plant’s energy into the fruit. Some gardeners gently lift and move the vines to run in one direction to make access easier. Trim main vines and lateral vines as needed again later in the season.
     Fertilizing – Fertilize plants with a water-soluble fertilizer every week according to label directions. Apply the liquid fertilizer to the soil around the base of the plant. The fertilizer should supply nitrogen, phosphorous, and potassium. Alternatively, you can apply a complete fertilizer around the base of your plant every 2 weeks. But beware, over-fertilization can cause excessive vine growth and split your pumpkins.

Harvesting  

  • Generally, pumpkins are harvested in late September or October before heavy frosts hit the planting area.
  • Use a sharp knife or pruning shears to cut them from the vines, leaving 3 to 4 inches of stem attached to each fruit. 
  • Try to avoid cutting or bruising the fruit.
  • The rinds need to be hard and firm for pumpkins to store well.

Storage and Preservation

  • Store pumpkins in a dry area that stays between 50 and 55 degrees F. 
  • For pumpkins that ripen before Halloween, wash them with a weak bleach solution (1 TBS. mixed in 16 oz. of water), rinse with water, and store them in your basement on a pallet or platform that allows air to circulate around the fruit.

 

Back to top

Maintained by the IET Department of the College of Agriculture and Natural Resources. © 2020. Web Accessibility

University programs, activities, and facilities are available to all without regard to race, color, sex, gender identity or expression, sexual orientation, marital status, age, national origin, political affiliation, physical or mental disability, religion, protected veteran status, genetic information, personal appearance, or any other legally protected class. If you need a reasonable accommodation to participate in any event or activity, please contact your local University of Maryland Extension Office.