Master Gardener: Starting an asparagus bed

Jerry Vitalis
Jerry Vitalis

As I write this article, we are receiving a fresh blanket of snow that will end up being several inches.  I have written articles on asparagus for many years, but each article is different because of a different type of spring.  Each spring when we order our bare root plants, we are always pleasantly surprised at how many new asparagus beds are being started.

For many years, we sold either Mary or Martha Washington — that is an old, reliable variety that makes up most of the asparagus patches in the area.  This year, we are offering Purple Passion and Jersey Knight.  Purple Passion has a rich color with large sweet spears that turn green when cooked. I have some of these and the stalks are very large, yet sweet and tender.  We finally offered some Jersey Knight — that is a newer variety that is an all-male strain, meaning the ferns don’t go to seed.  Another nice feature of this variety is that it’s rust resistant with strong spears, yet super tender.

Planning an asparagus bed is almost as important as the planting.  Asparagus roots can be grown on sandy soils to heavy clay loam.  However, the highest yields are obtained on deep, sandy loam that is well drained.  A couple of reasons asparagus roots should be planted away from trees and shrubs is because they need the sunlight and moisture that shade will rob them of, reducing the yield.  A good asparagus bed should last about twenty or more years.  The number one enemy of a veteran bed is weeds.  The best planning includes using herbicide a year prior to planting to rid the area of weeds.  Regardless if this possible or not, one must keep all seeds out of the bed to preserve the long life of the asparagus plants.

The plants we sell are two-year-old plants, and I have had great success in starting asparagus.  However, I once said the same for raspberry canes and have had trouble ever since.  When you are ready to plant, dig a trench about eight to ten inches deep and wide enough to be able to spread the roots.  If you have never seen an asparagus root, they look like an octopus with many legs.  Space the plants eighteen inches apart and if you have more than one row, leave four feet between the rows.

I always put water in my trenches so I plant in mud, but that’s me.  Cover the roots with at least two inches of soil above the crown.  The important part is the soil along the trench, which will be used to cover the shoots as they come up, much like you would do with dahlias and gladiolas.   Continue to fill in the trench as the ferns continue to grow, placing loose dirt around the plant without covering up the fern.

Asparagus roots handle dry weather quite well, but since this is a new patch, keep it from getting too dry.  Keep the weeds out and remember not to harvest for at least two years.

— Jerry Vitalis is a Chisago County Master Gardener

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