Three Benefits of Native Plant Roots

The other day I was watching a show on television that was trumpeting the benefits of organic matter.  It really made me think.  I know organic matter doesn’t exactly get everyone fired up, but one comparison that was presented in this program really opened my eyes to the benefits of prairie plants to the soil.

They took soil samples from the edge of a field, which was untilled remnant prairie, and from the farm field itself.  The prairie edge had nearly six percent organic matter, while the field ranged from two to three percent organic matter.  That may not seem like a big deal, but the prairie provides tremendous improvements to the soil.  There is so much going on underground in a prairie.  Here is an explanation of what native plant roots do for the soil:

They add organic matter.

Organic matter is extremely important in a healthy soil.  It attracts microbes, earthworms, and fungi that bring the soil to life.  These organisms break down the thatch at the surface as well as the roots that die from year to year.

Organic matter reduces compaction, making the soil spongy and able to bounce back.

In addition, organic matter increases the water holding capacity.  It is said that for every one percent of additional organic matter, the soil can receive four percent more water holding capacity.  This is important through prolonged periods without rain.


Western Kansas Prairie-Photo by Larry Vickerman

Organic matter helps prevent soil and wind erosion by binding sandy soil particles together.  This binding property of organic matter prevents caking, cracking, and water run-off that occurs when clay soils dry.

They add nutrients.  

The breakdown of organic matter consequently infuses minerals throughout the soil profile.  For every one percent of organic matter in the soil, it releases on average:

  • 20 to 30 lbs. of Nitrogen
  • 4 to 7 lbs. of Phosphorus
  • 2 to 3 lbs. of Sulfur

Organisms in the soil are vital in the decomposition process.  They help recycle the nutrients into forms that are readily available for plants to absorb through their roots.  It is a symbiotic relationship.  Other plants, like legumes (prairie clovers, lead plant and indigos), actively fix nitrogen from the air and add it to the soil.  These native plants live harmoniously together, forming a matrix of roots that keep giving back to the land.


Purple Prairie Clover at Dyck Arboretum of the Plains

They improve soil porosity.

What we see above ground is only 1/3 of the entire prairie plant.  The roots are 2/3 of the plant and 1/3 of those roots die each year, adding organic matter to the soil and opening pores, so water can percolate deeply into the ground.  If you have a heavy clay soil, native grass roots can break through compacted soils.  It is rare to see standing water in a prairie because of the holes punctured deep into the earth by plant roots, allowing rainfall to be readily absorbed.


The rich soils of the prairie that were broken for farming were a result of huge quantities of organic matter.  In some places in the Tallgrass Prairie, the top soil was over ten feet deep from centuries of organic matter decomposition.  Think of the prairie soil as a living organism that gives and takes and gives and takes.  It is true, prairies develop healthy soils.  Why not start bettering your own soil by growing a prairie?

Is Your Gumbo Soil Making You Sing the Blues?

Our soil here in Kansas is gumbo.  Not the delicious soup, but heavy clay.  It is clay all the time and all the time it is clay.  I have tried to describe it to others, but it needs to be experienced.  They may say they have something similar, but for us who endure it and garden in it and curse it, it is exasperating.  Unbelievable, really.

Clay soil is often too wet or too dry.  When wet, it sticks to your shoes and tools like a leach.  Every step you take makes you one inch taller.  When dry, it is like concrete, impenetrable, and cracks wide open.

Do you ever feel like you need one of these to work in your clay soil?

Do you ever feel like you need one of these to work in your clay soil?

I had a gentleman from Ohio work with me one spring.  Every morning with anticipation I awaited his next derogatory comment about our clay soils.  He really grew to dislike it and even questioned my sanity for trying to garden in it.  “I have never seen anything like it!” he said.  He was so ready to go back home to his beautiful Midwestern soil.

Our soil is amazing stuff – no doubt – and it presents challenges for growing plants. But let’s take a look at some of the pros and cons of clay soil.

Positives of clay soils (Yes. There are a few.)

  • It holds water well – The fine particles are porous retaining water and holding it tightly.
  • It holds nutrients well – The tiny particles are negatively charged attracting many positive elements like phosphorus, potassium and other minor nutrients.

Negatives of clay soils

  • Low water infiltration rate (usually one inch per hour)
  • Shrinks and swells with moisture
  • Keeps root zone wet for prolonged periods, which is problematic for drought-tolerant native plants
  • Slow to warm in the spring
  • Compacts easily when worked wet
  • Often so tight that plant roots cannot grow

Tips for improving clay soils

So, do we have any hope of improving our clay soil? It can be done, but will require some work.

  • Organic matter, organic matter and more organic matter is what it will take to improve your soil.  Put down at least six to eight inches of organic matter on the entire area you want to enhance.  Organic matter can include shredded leaves, compost, grass clippings or aged manure.
  • Next, you must till the organic matter into the soil to a depth of at least six inches or deeper.  Keep in mind that the deeper you go the more benefit to the soil you will realize.
  • When complete, the bed will be built up several inches.  Not to worry, it will settle over time as the organic matter continues to break down and melt into the clay.  It will take several seasons to fully accomplish the desired result which is a soil that is manageable.
  • Add organic matter on an annual basis for a garden or initially when establishing a new display bed.
Planting Shrubs in our Prairie Window Project

Volunteers planting shrubs in our Prairie Window Project.

It is very difficult to improve an established bed.  Adding mulch will improve it over time as the mulch begins to decompose.  Any new plants that are established can benefit by digging a hole at least twice as big as needed and incorporating compost and existing soil together as you back fill around the root ball.  Don’t just put compost around the roots as you back fill, because it will discourage the plant from rooting out into your gumbo soil.  It is essentially like repotting the plant in the soil.  The roots will only grow in the loose compost.

You will be rewarded for your efforts.  Even a little compost mixed with your gumbo will improve your soil.  Mulch it with two to three inches of mulch and over time you will develop a soil where plants thrive.  Don’t let your soil get the best of you.