How should asparagus beds be prepared for winter?
Written by
Julia Anderson
Reviewed by
Prof. Samuel Fitzgerald, Ph.D.Preparing asparagus beds for winter protection saves the crowns from hardships that would make the following spring's growth weak, if it grew at all. I usually begin when the first biting frost beyond the killing point makes complete work of the ferns. This occurs in my gardens when the thermometer drops to 28° for several consecutive nights due to frost. You have an investment to protect that will yield you a return for many years.
Fern Removal
- Cut ferns 2 inches above soil after complete dieback
- Dispose of debris away from beds to prevent rust spores
- Sanitize tools with 10% bleach solution between plants
- Complete before heavy snowfall or freezing rains
Soil Protection
- Apply 6-inch straw mulch over crowns after cleanup
- Avoid hay which contains weed seeds
- Use shredded leaves as alternative insulation
- Maintain mulch layer through winter winds
Pest Prevention
- Install wire mesh barriers against voles and mice
- Bury edges 6 inches deep around bed perimeter
- Place rodent repellent sachets at corners
- Check monthly for tunnel breaches
Prevention of disease under bed sanitation is essential. It is advisable to remove all traces of plants, dead spears, and bits of fern. It nurtures the spores of the fungi, which are sure to start again in the spring. It is my practice to burn all diseased material rather than compost it. Thus, I prevent the rust and fusarium from wintering.
In a bit more severe area in zones 3-4, add: extra insulation with burlap over mulch, please don't try staples, use a rock instead to hold burlap down. Ventilate a bit during winter thaws to avoid crown rot. I just keep an eye on soil temp, should stay 25-35F under cover, they freeze at 15F without it.
Perform a final soil test before freeze. If necessary, adjust the soil pH to a range of 6.5 to 7.0. If required, liming and other amendment products should be used in place of fertilizer for effective nutrient management. In addition to providing a spring reference point, recording the soil test result prevents any potential adverse impacts on nutrient balance before the next growing season.
Check rodent barriers monthly, particularly after snowstorms. Rerefill tunnel entrances with gravel. Refill repellents. I use castor oil granules as the repellent of choice. Also, I pack snow over beds for extra insulation, as many of my beds are exposed to winter winds. With the proper attention to winter care of my beds, by the spring, I assure myself of many vigorous spears.
Read the full article: When to Plant Asparagus: Essential Growing Guide
