Pumpkins are a summer-growing annual. Like all annuals, they are able to complete their life cycle within one growing season. Despite a growing range that encompasses much of the United States, pumpkins are most productive while the temperatures are warm throughout the day and night and do not tolerate cool temperatures. New plant seeds should be planted every year in the late spring or summer.
Life Span and Frost Tolerance
Vegetables may be classified as annual or perennial, as well as cool and warm season. Perennial, cool-season vegetables, such as asparagus and rhubarb, are able to live for several years and withstand frost. Some annuals, called hardy annuals, only live one year, but they are able to withstand light frost. Onions, peas and potatoes are examples of hardy annual vegetables. Others, such as pumpkins, are tender annuals. Tender annuals only live one year and do not tolerate frost.
Pumpkin Plant Description
For the most part, pumpkins belong to either the species Cucurbita pepo or Cucurbita maxima. Cucurbita pepo are commercially produced for making jack o'lanterns, while Cucurbita maxima produce excessively large pumpkins, most often used in growing competitions. All species of pumpkins grow in long vines, up to 3 feet tall and 15 feet long. Crops come in a variety of colors; however, the color orange is by far the most pervasive color. A pumpkins is ready for harvest once color is solid and the rind is hard.
Pumpkins are typically germinated by seed. However, wait until the threat of frost has completely passed before planting any pumpkin seeds outdoors. Seeds will not germinate, and may even rot, if placed in soil that is less than 60 degrees Fahrenheit. For optimal seed germination, plant seeds when the soil temperature is between 70 and 90 degrees. Most pumpkins take between 85 to 120 days to ripen on the vine. For Halloween pumpkins, plant seeds between late May and early July. Northern growers should plant at the early end of that range, while southern growers should wait until later in the season. Plant seeds about 1 inch deep, leaving 5 feet between rows.
Pumpkins are easy to grow, low-maintenance plants. They tolerate hot temperatures, soil that is only moderately fertile and even drought. For best results, water pumpkins regularly and deeply. Provide at least 1 inch of water per week while fruit is forming. In most locations, once a week watering should be sufficient, with the exception of pumpkins grown in very sandy soil. These plants may require irrigation twice a week. Maintain a layer of mulch around plants to discourage pervasive weed growth.