Yellow squash belongs to the summer squash family along with the zucchini and scallop squash. Its pale yellow fruit is prized in a variety of dishes from stir-fries to roast vegetable recipes. It produces heavily throughout the summer months, with each plant turning out several squashes a week at the peak of production. Harvesting the yellow squash at its pinnacle of ripeness ensures it is tender yet flavorful, as overly ripe squash is tough and unappetizing.
Inspect the base of the squash where it connects to the vine. This area should be one to two inches in diameter when ripe. Depending on the variety of squash, the squash should be between approximately three to six inches long.
Pick the squash when the base is the correct diameter and when the color is still pale yellow. Once the color darkens or starts to get an orange tint, the squash is overripe.
Press your fingernail into the skin of the squash. If your nail cuts the skin, the squash is ready to use. If the skin is too thick to pierce, dispose of or compost the squash as it is overripe, which makes it hard and overly fibrous.