These squash should be harvested when they are about 3 to 4 inches in diameter for the best tenderness and flavor. They are typically ready for harvest in 45 to 55 days from planting. Round zucchini should be planted in warm, well-drained, and fertile soil. They thrive in full sun and require regular, deep watering, especially during the growing season. They are also sometimes referred to as “8 ball zucchini” due to their round shape resembling a pool ball.