Green Asparagus Seeds · Asparagus is planted in the ground three years before it can be harvested for the full season. First comes the seed then comes the plant. Farmers only harvest for short period of time the first few years to allow for further growth. The mature plant is harvested all season which typically stretches up to 90 days. Asparagus will grow sometimes 6 to 7 inches in one day! An Asparagus plant will generally produce from 8 to 12 years depending on different factors.