Asparagus Planting Guide
Asparagus beds last a long time, up to 25 years, so give careful consideration to where you plant. Asparagus requires good drainage. It will die if the roots sit in water. Research has shown that asparagus spears are tougher after exposure to cold spells in the spring. Given this, an ideal location would have a sunny southern exposure against a wall. Mixing sand in the soil will help the soil warm in the spring and improve drainage.
The usual method for planting asparagus is to dig a trench 12" deep and 12" wide for a single row. If you want a double row, the trench needs to be at least 24" wide. There is evidence that 24? between crowns in double rows yields significantly more spears. Fill the bottom 2" of the trench with rotted manure or compost, forming it into a ridge down the center.
Plant your crowns 10" - 12" apart in the rows, spreading the roots over the ridge of compost so they lay flat. Replace the soil from the trench in 2-3" layers over several weeks, keeping a ridge at the center to prevent puddles. Keep watered and free of weeds. You may mulch with straw or leaf mold at midsummer. Do not cut the ferns. If you live in an area with hard winters, the ferns hold the snow and protect the bed from heaving. If you live in an area with mild winters, you can cut the ferns in the late fall after they turn brown and dry.
Growing & Harvesting
Asparagus must be grown for two full seasons before it can be harvested. If you harvest or damage the ferns during this period you will reduce your yields for the life of the bed. In the first year of harvest (year three after planting), pick spears for two weeks only. In the fourth year of the bed you can increase the harvest to four weeks, and in the fifth year and thereafter you may harvest for eight weeks.
The correct way to harvest the spears is by breaking them off with your fingers at surface level. If you cut below the surface with a knife there is a chance you will damage the crowns. Research has shown that thicker spears are the most tender. Pick the big ones!