Asparagus grows best in fertile soils with a ph of 6.8-7.2. Choose a permanent sunny location which is well-drained. It is advisable to prepare the site a year in advance by removing all perennial weeds.
In early spring, apply 5 lbs of 5-10-10 fertilizer per 100 square feet and plow deep, working the fertilizer in well. Research has shown that a high phosphate fertilizer application (such as super-phosphate bone meal) when worked well into the furrow prior to planting is a positive cultural practice.
Plant in furrows 6-8 inches deep and 4-5 feet apart. Recommended spacing within the row is 12-14″. Lay crowns up and cover with 2 inches of soil.
As the fern grows through the soil, gradually fill in the trench using this process to eliminate small weeds. By summer’s end the furrow should be leveled. Side-dress in early August with 1 lb of 5-10-10 per 20 feet of the row and lightly work into the soil. Allow the fern to grow all season, irrigating when necessary – especially when the plants are small.
In early spring of the next year, cut the old ferns from last year at ground level. Fertilize with 1 to 1 ½ lbs of 5-10-10 per 100 sq ft and work lightly into the soil. Research has shown that cultivation may injure crowns, reducing the following year’s crop and the life of the bed. Control weeds all season and irrigate as needed.
Be on the lookout for asparagus beetles. These insects can cause considerable damage to an established bed. Other common pests are aphids and asparagus minor. In each succeeding year, a split application of a 5-10-10 fertilizer before and after the harvest period should fulfill your plant’s needs.
New research shows you can begin to harvest asparagus the year after establishment, cutting for 2 weeks. The third season, you can cut for 4 weeks and by the fourth season, you can cut for a full season. Be careful not to damage emerging spears when cutting below the soil surface. An alternative to cutting is to snap the spear.
Always maintain good growing conditions after harvest by keeping the field weed free and insect free. Do not remove any ferns until they die naturally in the fall. Leave the ferns tall in winter or cut to 12 inches in the late fall when they turn brown. The ferns will act as a natural mulch to catch snow. With a little care, you should enjoy an asparagus bed for many years.