Question: how long will zucchini grow?
Answer: Harvesting Zucchini Harvest zucchini when it is between 4 and 8 inches long and about 1 1/2 to 3 inches in diameter. Zucchini generally takes 35 to 55 days from planting until harvest. Zucchini fruit grows rapidly -- up to 2 inches per day, so it is best to harvest them every other day during the growing season.