How Long Can Sugar Pumpkins Stay on the Vine?

Thanksgiving just wouldn't be much of a holiday without pie -- especially pumpkin pie, which needs sugar pumpkins for a truly good flavor. Sugar pumpkins require a very long growing season. Popular varieties such as Small Sugar and Sugar Pie mature after 90 to 110 days after planting, depending on the variety, weather conditions and other factors. Sugar pumpkins can remain on the vine until just before the first hard frost. Severe cold will damage pumpkin flesh, turning it to mush -- wiping out your entire harvest.

Harvest sugar pumpkins, other pumpkin types and winter squash -- all members of the cucurbit family -- whenever they are fully ripe. Good, uniform orange color is one sign of ripeness and skin hardness another. When a fully orange sugar pumpkin's outer skin or rind is hard, meaning too tough to puncture with your thumbnail, it's ripe. Vines should also be dry. Cut the pumpkin stem to a length of 3 to 6 inches, using a sharp knife. Never tear pumpkins from the vine, to avoid damaging the stem and introducing bacteria or disease.

Many gardeners, small growers and pick-your-own pumpkin purveyors wait to harvest sugar and other pumpkin types until autumn's first light frost kills the vines, to allow cucurbit fruits still out in the garden or field as much time as possible to mature and also cure outdoors. If mature pumpkins are still outside when the first serious freeze comes, however, most of the crop will be lost. According to Maurice Ogutu of University of Illinois Extension, hard-frost injury to the fruit surface can cause fungal and bacterial rot that destroys 80 to 90 percent of a crop.

The curing process ripens immature pumpkins, heals wounds and fully hardens the rind or shell, helping preserve the fruit during storage. A standard indoor curing period is 10 days to two weeks, at temperatures between 75 and 85 degrees Fahrenheit and 80 to 85 percent relative humidity. Good circulation is also a plus. Curing pumpkins outdoors is feasible if conditions approximate these.

Ripe, fully cured sugar pumpkins will keep for two to three months when stored in a cool, dry place. Temperatures of 50 to 55 degrees Fahrenheit and relative humidity of 50 to 70 percent are ideal. Place your sugar pumpkins on wooden pallets in a storage area with flooring other than concrete. Put the fruits in a single layer on wooden pallets with enough space in between the fruits; make sure pumpkins don't touch each other. Use a fan to circulate air, and also let in cool outdoor air at night. Check your pumpkins regularly and remove any rotted ones to avoid spreading pathogens.