Download a pdf on Growing Asparagus
Steps to Succeed with this Perennial Vegetable
Asparagus is a very rewarding vegetable to grow, but it does take some effort to establish, and a few years to come into production. In the mild but wet winters of the Pacific Northwest, a little care in planting can reap big rewards. An asparagus bed takes room, and can be productive for years. Choosing varieties that are mostly male plants, like Jersey Knight, give you beds that are more productive and less prone to beetle infestations. Once established, asparagus beds are fairly easy to maintain.
Preparation for planting
- Asparagus can be grown from seed, but will take three or more years to come into production. Most gardeners start with crowns, which will start producing harvests the year after planting.
- Store the asparagus crowns in a cool, dry location until ready to plant. Do not store crowns in plastic bags.
- Choose a site with full sun– a minimum of 6 hours a day during the summer. Shaded beds quickly decline.
- Asparagus needs well-drained soil. Winter wet soil will lead to quick decline. On heavy soil, consider building a raised bed.
- Dig a trench 18″ wide and 6″-8″ deep. Mix the soil from the trench with compost or aged manure. Set it aside.
- If building a raised bed, work some aged manure or compost into the soil surface to a depth of 4″-6″. Plan on your raised bed to be 10″-12″ deep when finished.
- Soak the asparagus crowns for 1-2 hours in water.
- Lay the crown on the floor of the trench or raised bed.
- Spread each crown’s root mass out so they do not overlap– at least 12″ apart, preferably 18″ apart.
- Cover the crowns with 2″-3″ of soil-compost mix. Water in.
- As the spears begin to grow, slowly add more soil compost mix until the trench is full, or the raised bed in 10″-12″ high. This should take about 6-8 weeks.
Care and harvest of Asparagus
- The first spring, do not harvest any spears. The second spring, harvest spears sparingly. Stop harvesting when the spears are the diameter of a pencil or smaller. Established beds can be harvested usually for 6-8 weeks.
- Harvest the spears by cutting or breaking the stalk just above the soil.
- Water the asparagus bed during dry summer weather. Keep it weeded and mulched.
- Watch for and control asparagus beetles by hand picking, or with neem oil based sprays or spinosad. Control aphids with horticultural soap or a strong jet of water.
- If stalks begin to flop outward from the bed (they can reach 6′ or more in height), corral them with a couple of stakes and twine.
- After the stalks die down in winter, cut them to the ground and mulch the bed with compost. Fertilize each spring before the new spears appear with a good vegetable fertilizer.