You should harvest squash based on the type of squash and the maturity indicators:
- Summer squash (such as zucchini) is best picked throughout the summer when the fruits are about 6 to 8 inches long. They taste best at this size and will have tender skin. Picking them frequently encourages more production. Avoid letting them get too large as they become tough, seedy, and bitter. Use sharp garden shears to cut the squash from the vine and leave about an inch of stem for longer shelf life.
- Winter squash (such as butternut, acorn, and pumpkin) is usually harvested once at the end of the growing season, around the first frost or when the vines naturally die back. Indicators of maturity include thick, tough skin that can't be punctured by a fingernail, a woody stem that is no longer green, deepened skin color, and the squash sounding hollow when tapped. Harvest before heavy frost or damaging weather. After cutting, cure winter squash by leaving it in the sun or a dry warm place for several days to harden the skin and improve flavor and storage life.
- For butternut squash in particular, expect about 80 to 110 days from planting to harvest. The squash changes from green to tan color when ready. Curing at room temperature for about a week or more improves sweetness and storage.
In summary:
- Pick summer squash young and frequently at about 6-8 inches.
- Harvest winter squash fully mature and before frost, using color, skin toughness, stem drying, and hollow sound as guides.
- Cure winter squash after harvesting for best taste and shelf life.
This approach ensures the best flavor and longevity for your squash harvest.
