Planting asparagus in a raised bed :
- Place the raised bed in a sunny location of the yard that receives six to eight hours of sunlight daily. Asparagus plants can tolerate some light shade. It is best to have a raised bed that is at least 12 inches in height to accommodate the growing root systems of the asparagus plants.
- Fill the raised bed with good-quality topsoil that is blended with compost or other organic matter such as manure or peat moss.
- Lay a black plastic over the entire raised bed, covering the soil. This will help to retain heat within the soil for an early spring planting.
- Purchase 1-year-old asparagus crowns. Ensure the asparagus crowns you purchase are healthy and male.
- Soak the asparagus crowns in a bucket filled with warm water for one hour.
- Remove the black plastic when the last frost date has passed. Dig trenches 8 inches deep and 5 feet apart with a garden trowel.
- Plant the crowns about 8 in. deep and 15 in. apart.
- Cover initially with 2 in. of dirt, and gradually fill the trench as the spears emerge.
- A newly planted asparagus patch should not be harvested for its first year -- it needs this time to become established in the garden. The second year, you can harvest selectively over a two-week period. The third year, harvest over four weeks. The fourth year and beyond, you may harvest over an 8- to 10-week period, up until new shoots emerge thin and spindly
- Snapping of the spear by hand is easy and protects the plant. You can use a knife, but be careful not to damage developing stems.
- At the end of the harvest, allow the asparagus plants to form ferns. These help transfer energy to the roots for good spear development the next season.