Summer Squash: Include crookneck, pattypan, straight-neck, scallop, vegetable marrow, and zucchini.
Pick summer squashes young when rinds are still tender and before seeds have formed. Harvest zucchini and crookneck varieties when they are 5 to 10 inches long (4 to 7 inches long for yellow varieties); harvest scallop and round types when they are 3 to 5 inches in diameter. Break the squashes from the stem, or use a clean knife to cut the fruit away. Do not let summer squash mature; that will suppress flowering and reduce the yield.
Winter Squash: Include Hubbard, butternut, acorn, delicious, banana, Turk’s turban, cushaw, and spaghetti squash.
Winter squashes are ready for harvest 60 to 110 days from sowing when rinds are full color and firm (some acorn squash may be green and have semi-hard rinds). Winter squashes should be allowed to mature fully on the vine. If the rind cannot be dented with your thumbnail, it is ready for harvest. Cut squash from the vine leaving 2 to 3 inches of stem above the fruit; this will allow the squash to store longer.