What takes 45 days to grow?
Spinach grows super fast from seed, taking only 40 to 45 days to reach maturity, but you can actually start harvesting baby spinach leaves after just 25 to 30 days, depending on the variety you’re growing. Learn how to grow your own organic spinach. Spinach. Spinach is a versatile and fast-growing green that can be harvested in as little as 20-30 days. It thrives in cooler temperatures and prefers partial shade. Sow the spinach seeds directly in the soil, and keep the soil moist for the best results.