We’ve been growing asparagus here at the farm since 1982. There really is nothing quite like the taste of fresh asparagus to kick-off spring. It can take up to 3 years for this perennial vegetable to become fully established (although you can harvest it after 1 year), and can be harvested for up to 20 years!
Asparagus grows best in fertile soil, with a pH of 7.0. Choose a location with full sun that is well drained. Preparing your planting location a year ahead is best, but not necessary. Make sure to remove all perennial weeds and to apply lime if you need to adjust the pH.
Planting Asparagus Roots
In the early spring, apply 5lbs of 5-10-10 fertilizer (or equivalent) per 100sqft and plow deep, working the fertilizer in well. Plant in furrows, which are 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. Within 6 weeks, the furrow should be leveled. Side-dress in early August with 1lb of 5-10-10 (or equivalent) per 20 feet of row and lightly work into the soil. Allow the fern to grow all season, irrigating when necessary, especially when the plants are small.
Asparagus Root Bed Maintenance
In early spring of the next year, cut the old ferns at ground level. Broadcast lime and 11/2 lbs. of 5-10-10 (or equivalent) per 100 square feet. Work lightly into the soil, so as not to damage the crowns. NOTE: Researchers have demonstrated that cultivation may injure the 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, as these insects can damage the crop. If present, use any mild garden insecticide available at garden centers. In each succeeding year, a split application of 5-10-10, before and after harvest should fulfill your plants’ needs.
New research suggests that you can begin to harvest asparagus the year after establishment, cutting for two weeks. The second season you can cut for four weeks, and by the third season you can cut for a full season (6 weeks). 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, keeping the field weed 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 brown. This will catch snow for natural mulch. With a little care you should enjoy an asparagus bed for ten to fifteen years.