Preparing Your Soil for Winter by Nancy Shepard

 

Photo by Lukas. Pexel.com

By November you’ve probably pulled out your dead vegetable plants, pulled out plant stakes, cleaned up your perennial areas, and mulched the leaves over your lawn. But what about your soil? We usually think of our garden soil in the spring when we get ready to plant and want to amend it. But you can do some beneficial things for your soil before winter arrives.

Amend your soil

Fall is an excellent time to amend garden soil.  Well-rotted manure, compost, and leaves can all be incorporated before the ground freezes, enhancing beneficial microorganisms and soil insects.

Photo: Sippakorn Yamkasikorn, Pexels.com

I attended a presentation this October by Dr. Tamla Blunt, CSU Bioagricultural Sciences and Pest Management Department called “Putting the Garden to Bed.” She named the benefits for doing mulches, cover crops, compost or manure to cover and protect the soil:

• Makes it difficult for weed seeds to germinate or seedling weeds to survive
• Reduced evaporation from soil surface and stabilizes soil moisture (dry soil gets colder faster than wet soil)
• Improves the soil tilth and helps lessen soil compaction
• Moderates soil temperature extremes and controls erosion

Why do we want to do these things? The microbes for a healthy living ecosystem. As Dr. Blunt said, “the main criteria for soil health is the presence of active organisms in the soil such as insects, worms and microorganisms.”

What to use

To organically amend soil, add a two-inch layer of organic material over the surface of the soil and mix it into the top four to six inches. Add four cubic yards of organic amendment per 1,000 square feet of soil area. [https://planttalk.colostate.edu/topics/soils-amendments-composting/1605-soil-preparation/]

Organic matter such as herbivore-generated manure – horse, cow, goat, llama or rabbit droppings are all equally good [https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=28295]

For vegetable gardens, a green cover crop or a straw-covered layer of manure will work slowly over the winter to enrich your soil, attract earthworms, and feed the legions of beneficial microbes needed for healthy spring crops. [https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=28295] 

Compost – your own or purchased

Besides manure, your can use bark chips, grass clippings (herbicide free), and leaves

Straw on top with 3-4 inches is good for weed control. Use organic straw to avoid herbicides and as Dr. Blunt recommended, make sure you don’t mix in the straw with the soil later as it can disrupt the carbon/nitrogen ratio. Just use it as a cover.

Photo: Gretta Hoffman, Pexels.com

To till or not?

I also recently attended a presentation by Soil Ecologist, Jean Reeder, Ph.D. After retiring from the USDA as a research scientist, Jean is now a soils instructor for the CSU extension, Denver Botanic Gardens, Front Range Community College and local nurseries.

In my research I found differing points of view on whether to mix in soil amendments or not.  Dr. Reeder promotes disturbing the soil as little as possible so as to not disturb the microorganisms keeping the soil healthy. Other sources from universities say to only incorporate amendments 4-6 inches into the soil. But the conclusion I came to was that we shouldn’t be doing the deep rototilling that was recommended in the past. Even commercial farmers are starting to learn that heavy tilling decreases the health of the soil and thus their crop output. [https://www.usda.gov/media/blog/2017/11/30/saving-money-time-and-soil-economics-no-till-farming]

Consider soil testing now

Gardeners should test their soil at least every three years and fall is a great time to get a test. You’ll usually receive results in a few weeks. This is helpful before you lay down your organic mulches. Researchers at the University of St. Thomas reported in a 2019 paper that garden plots that rely primarily on compost inputs can have too much phosphorus which can result in soil and water pollution. [https://iopscience.iop.org/article/10.1088/2515-7620/ab3b8c] Testing your soil regularly can help you ensure that your plants are getting what they need without damaging the environment. [https://extension.umn.edu/yard-and-garden-news/prepare-your-vegetable-garden-winter]

CSU does soil testing, although their lab is not accepting samples until November this year.  See this site for more information: [https://soiltestinglab.colostate.edu/]

So just when you thought you had all your fall garden chores done, think about giving your garden soil some amendments that can break down, start releasing nutrients, and protect and keep your soil healthy through the winter.