Asparagus is a hardy perennial vegetable that can remain productive for 15 years or more.
Site preparation is essential for success. Thorough soil preparation is required to obtain a good crop. Eliminate weeds before planting. The best results are achieved on light, sandy soils. On heavy soils, asparagus is best grown in raised beds. Asparagus requires a high pH of 6.5-7, so test your soil and amend accordingly. It is best to test and begin amending soil the year before planting.
One crown will supply approximately 1/2 pound of spears when the plants are fully established.
Trim off about 1/4 of the root tips at the time of planting. Dig a hole 8” deep and backfill with 2”-4” of good soil and manure. Apply either 1 lb. of Triple Superphosphate (0-46-0) or 2 lb. of Superphosphate (0-20-0) per 50 feet of row directly in the trench. This fertilizer, which contains no potassium or nitrogen, will not burn the crowns. Place the crowns at this depth with the buds on top and the roots spread out. Plant 15” apart with 40”-48” between rows to give the developing ferns room to grow. Cover the crown with soil. As soon as shoots appear, add more soil. Keep repeating this process until the hole is level.
Don’t harvest the first two seasons. Harvest the third year by cutting spears just below the soil level or by snapping off the spear. Whether you snap or cut spears does not appear to make a difference to the plant. Harvest when spears are about 8”-10” tall. Stop harvesting spears by late June. Do not cut down or prune the fern until late fall as the tops will be storing food in the roots for next year’s crop.
Fertilize every spring and after harvest with 5-10-5 fertilizer.
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