The Blue Hubbard is a massive, heirloom winter squash (Cucurbita maxima) known for its distinctive slate-blue rind and exceptionally sweet, orange flesh. This variety has one of the longest growing seasons, often requiring 100 to 120 days to fully mature on the vine. The reward for this patience is a superior flavor profile and the ability to store the squash for many months through the winter. Achieving this long-term storage depends on waiting for the moment of full maturity before harvest.
Visual Signs of Readiness
Determining the harvest time requires looking for a combination of specific physical changes, as harvesting too early results in bland flavor and poor storage life. The condition of the plant itself signals it has finished supplying nutrients to the fruit. Wait until the main vines begin to naturally dry out and die back, shifting from green and pliable to brown and brittle.
The skin’s appearance also changes, transitioning from darker green to the signature slate-blue or gray-blue color of the mature Blue Hubbard. A more important test involves the rind’s hardness: a mature squash will resist puncture when pressed firmly with a fingernail. If your nail easily breaks the surface, the fruit is not fully mature and should remain on the vine to develop its protective outer shell.
The stem connecting the squash to the vine should look dry, shriveled, and feel hard and woody, a process called “corking.” This cork-like appearance confirms the fruit has sealed itself off from the vine and is no longer drawing water or nutrients, signifying that the sugars have concentrated and the squash is ready for picking.
Proper Harvesting Technique
Once maturity signs are present, the physical act of harvesting must be performed with precision to prevent rot during storage. Use a clean, sharp knife or pruning shears to cut the squash from the vine. It is necessary to leave a 1 to 2-inch piece of the stem, called the “handle,” attached to the squash.
Never break the squash from the vine or carry it by the stem. A broken or missing handle creates an open wound where bacteria and pathogens can enter the fruit. This entry point significantly shortens the storage life. Handle the large, heavy fruit with care to avoid any nicks, bruises, or cracks in the rind, as these physical damages compromise the squash’s protective layer.
Blue Hubbard squash is sensitive to cold, so complete the harvest before the first hard frost (temperatures below 45°F). Frost damage quickly ruins the quality of the flesh and severely reduces the squash’s ability to store well.
Curing and Storage Preparation
Blue Hubbard squash must undergo a curing process immediately after harvest to prepare it for long-term storage. Curing involves placing the squash in a warm, moderately dry environment for a period of 7 to 14 days. An ideal curing location maintains a temperature between 70°F and 80°F.
This warm treatment allows minor surface scratches or cuts to heal over and further hardens the rind. Curing also permits excess moisture to evaporate from the flesh, which concentrates the sugars and enhances the flavor profile. After curing, the squash is ready for preservation, extending its usability for up to six or seven months.
The cured squash should be moved to a cool, dark, and dry area for storage, ideally maintaining a temperature between 50°F and 55°F. A relative humidity of 60 to 70 percent is best to prevent the squash from shriveling. Storing the squash at temperatures below 50°F can cause chilling injury, which degrades the quality and shortens its shelf life.