Autumn is the right season to harvest ripe butternut squash. Like other winter squashes, butternut squash should not be consumed prior to ripening since the taste has not developed yet. The color, weight, and texture of the skin all indicate whether or not the squash is ripe.
As it starts growing, the skin of butternut squash has a yellow-green hue. This color turns deeper as the squash matures. A ripe butternut squash has a beige skin with no trace of green. The flesh of a ripe squash should be deep orange.
When selecting a ripe butternut squash, a consumer should pick each squash up and examine it thoroughly. These squashes are heavy when fully mature. Most ripe butternut squashes weigh at least 2 pounds (about 1 kg). Knowledgeable consumers also tap on the squash and listen to the resulting sound. A ripe squash sounds hollow inside, rather than sounding thick or solid.
The texture of the skin also reveals a lot about whether or not the squash has fully matured. An individual should attempt to press his or her thumbnail into the skin of the squash prior to selecting it. Ripe butternut squash has tough skin that does not break under the pressure of an individual's thumbnail. The skin of a mature squash also appears dull, while an unripened squash has shiny skin.
Ripe butternut squashes have a sweet, vaguely nutty taste comparable to the taste of pumpkins or sweet potatoes. Their taste makes them suitable for use in everything from soups to breads. Unripe squash is relatively bland and tasteless in comparison.
Many varieties of butternut squash take between four and five months to ripen after the seeds are planted. Gardeners and farmers typically plant butternut squashes in spring and harvest them in the middle of autumn, usually around late September or early October. If harvested before this time, the squashes are less likely to be completely ripe. Butternut squashes should also be harvested before any heavy frosts occur since frosts can prevent squash from ripening. If frost comes a couple weeks early, butternut squashes can be brought inside and ripened indoors.
When ripening indoors, the farmer cuts the squash from the vine and wipes it down to reduce the risk of mold. He or she then places the unripened squash in a warm, sunny location and turns it periodically to ensure that all sides have access to the sunlight. This process only works if the squash simply needs to finish ripening for a few days, however. Individuals should not attempt indoor ripening before the butternut squash develops its trademark bell-shape and grows to its full size and weight.