There are a couple of things that should be done to winterize your asparagus patch. In the late fall or early winter you should cut back your asparagus ferns. This will help to break the pest cycle of the asparagus beetle that loves to overwinter in the ferns. Wait until the leaves are yellow and brown. Then cut them down with good sharp pruners. Make sure to leave about 2 inches of the asparagus plant above the surface. If you cut them too low, that can cause damage to the crown, or growing point. After you have cut them back add about 4 inches of mulch to protect the roots from any winter damage. Finally, make sure you put the cut ferns far away from your asparagus patch. A compost pile is a good spot. I put them in a far corner of the garden and let the chickens peck at them. They like to pick at the berries and seeds, and they love to walk and sit on the soft ferns.
Asparagus ferns ready to be cut
Asparagus cut, make sure to leave 2" above the ground
Then add 3-4" of mulch for winter protection of the roots
~ Phil Williams
Phil Williams is a permaculture consultant and designer and creator of the website foodproduction101.com. His website provides useful, timely information for the experienced or beginning gardener, landscaper, or permaculturalist. Phil's personal goals are to build soil, restore and regenerate degraded landscapes, grow and raise an abundance of healthy food of great variety, design and install resilient permaculture gardens in the most efficient manner possible, and teach others along the way.