Summer squash are harvested and eaten while immature while winter squash mature before being used or stored. Squash grow best in full sun and on loam soil high in organic matter. Squash are usually planted in hills near the end of May. Plant seed 1 to 1 1/2 inches deep. Plant 4 seed per hill then pull out all but the strongest two seedlings. Space summer squash hills 3 to 4 feet apart with hills of winter squash 4 to 5 feet apart. Use one large teaspoon of 5-10-5 fertilizer per hill, at planting time. Fertilize again, with 1 cup of fertilizer per 25 feet of area covered by the vines, at fruit set. Some vines may be cut off but allow fruit to set, then cut off the vine beyond the last fruit.
Harvest immature summer squash while the rind is easily punctured by a thumbnail. Zucchini and crooknecks should be 6 to 8 inches long and 3 inches in diameter. Scalloped or patty pan squash are harvested when grayish or greenish white but before they turn ivory. Harvest spaghetti squash when the rind turns golden yellow. Banana squash is harvested when golden orange.
Winter squash ripen on the vine and develop their characteristic color before harvesting. When ready, the rind is hard enough to resist puncturing by a thumbnail. Harvest before hard freezes, take 2 to 3 inches of stem and avoid bruising the fruit. Squash harvested with a stem left attached store best.
The first blossoms are male so incapable of setting fruit. If after a few days fruit are not being set, the problem may be lack of pollination.