Emmalea Ernest, Extension Fruit & Vegetable Specialist; emmalea@udel.edu
Proper harvest and post-harvest handling are important for fall harvested crops intended for extended season sales. For all crops discussed below, minimizing injury during harvest, and storing only disease-free produce is important to successful long-term storage.
Winter Squash
After harvest, winter squash should be cured for 10 days at 80-85°F and 75-80% relative humidity. If weather conditions are favorable, squash can be cured in the field after cutting. If not, they should be cured in a well-ventilated indoor space, such as a greenhouse or high tunnel. After the curing period squash should be stored at 55°F and 50-70% relative humidity. Temperatures below 50°F in the field or in storage can cause chilling injury and reduce quality. Cucurbita pepo types (i.e., acorn, delicata) will store up to 8 weeks, butternut squash and hard-shelled squash can be stored for at least 3 months. Some types of hard-shelled squash will store up to 6 months.
Cole Crops
Cabbage, cauliflower, and Brussels sprouts should all be stored at 32°F and 95% relative humidity. Cauliflower can be stored for 3 weeks in these conditions. Brussels sprouts that are left on the stalk for storage can last 6 weeks. Cabbage can be stored for at least one month but certain varieties will retain quality in storage for several months. Cabbage, cauliflower, and Brussels sprouts are all ethylene sensitive and should not be stored with ethylene producing fruits, such as apples. Ethylene exposure will cause leaf yellowing and abscission as well as curd discoloration in cauliflower.
Sweet Potatoes
Sweet potatoes intended for long term storage should be cured immediately after harvest for 5-7 days. Recommended curing conditions are 85°F at 85-90% relative humidity. The curing area should be adequately ventilated because roots undergoing the curing process consume oxygen and release carbon dioxide. After curing, sweet potatoes should be stored at 57°F and 85% relative humidity. Cured sweet potatoes may be held for up to one year. Sweet potatoes are sensitive to chilling injury from temperatures below 55°F.
Additional Resources
Post-harvest storage recommendations are given in each crop section of the Mid-Atlantic Commercial Vegetable Production Recommendations.
The USDA’s handbook titled: The Commercial Storage of Fruits, Vegetables and Florist and Nursery Stocks is a comprehensive resource with curing and storage conditions guidance for 138 different commodities.