Mushrooms in the Mulch

Mushrooms in the Mulch
Mushrooms in the Mulch

I have mushrooms in the mulch around my fruit trees.  Some of you may be aghast and the immediate question that comes to mind is, “how is he going to get rid of them?” 

I can answer the question quite easily.  I’m not.  I am going to let the mushrooms live out their life cycle and do their job in the organic system.  Yes.  They have a job and a very important one.

About the mulch

We spread the mulch around our apple trees and in front of our new cucumber bed earlier this year.  We used the sheet mulch method, adding a thick layer of cardboard to the surface of the soil.  This area was mostly bermudagrass with some weed tossed in for good measure and was a problem area to maintain.  We decided that a nice mulched area would make maintenance easier, and reduce the amount of grass that would eventually want to infiltrate into our new grow bed and around the trees.

It worked!  I keep a “no grow zone” around the edge of the mulch clear of any vegetation using my battery powered weed eater.  What bermudagrass does manage to get a slight foothold in the mulch is easily removed by hand.  The mulch provides an area around the apple trees that allows moisture to infiltrate and helps hold that moisture in the soil.   Moving the mulch aside reveals that we are beginning to develop a layer of soil much richer in organic material than before and life is much more plentiful in the soil. 

Getting things ready

We had a good run with our cucumbers this summer.  The bed was new, and the soil was my usual concoction of topsoil, composted cottonseed burrs, plus some worm castings, dry molasses, and greensand.  I top all of this off with a thick layer of wood chip mulch.  Our cucumbers did okay; about what I would expect for the first year in a newly constructed bed. 

We used or usual watering pattern, which is not a pattern at all.  We check the grow bed every two or three days during the hottest part of the summer, and if grow bed needs watering, we water though the surface drip system.  I water the turfgrass in the back yard with either a reciprocating sprinkler or a small pattern sprinkler that delivers a nice even gentle pattern.  When I water the turfgrass, I set the sprinkler to water the mulch around the apple trees.  The trees produced fruit this year for the first time since we planted them. 

The Rains Came

It rained heavily a few days ago and I noticed that a few mushrooms were appearing in the wood mulch.  This is not unusual.  The mushrooms you see pushing their way up in your landscape are the fruiting bodies of the fungi that inhabit the soil beneath the plants.  You don’t see these fungi when you dig in the soil.  They are microscopic and not easily visible to the naked eye except under certain conditions. 

There are thousands of different fungi living in healthy soil at any one time.  They perform different functions in the soil, all of which are a part of a healthy soil biome.  Many people wonder where the fungi originate.  There are fungi spores floating in the air all the time.  When they land on a spot that is favorable to their lifestyle, they populate that area.

What are these strange things?

The part that we see in our landscape are the fruits.  These mushrooms in the mulch produce the spores that go on to become more fungi.  This is all great, but what we are concerned with is what is going on in the soil and that area where the mulch meets the soil.

Mushrooms in the Mulch - Hyphae in wood chips

Fungi send our long filament structures called hyphae.  These structures are created by the hypha of the fungi.  Hyphae are truly amazing things for several reasons.

Hyphae can extend several yards beyond the fungi that spawns them.  These hyphae encounter the hypha of other fungi along the way.  Some simply ignore each other.  Amazingly, hypha from the same species interact and form networks of hyphae that can extend for hundreds of square yards.  Research has shown that in some old-growth forests, hyphae networks can extend for hundreds, if not thousands, of square yards.

Hyphae at work

The hyphae are the miners of the microbial world.  They are tiny and can work their way into the tiniest of cracks and pores of mineral deposits, usually in the form of rock in the soil.  They can extract minerals from those rocks.  These are the same minerals that plants need to grow healthy.  The hyphae extract these minerals in forms that are readily accessible by the plants. 

Fungi don’t use these minerals themselves.  Fungi need carbon to survive.  Where do they get it?  From the plants.  Plants create sugars as part of the photosynthesis process.  Some of these sugars are used to produce fruits. However, healthy plants produce much more sugar than they need.  The plants move those sugars to their roots where the sugars are exuded into the soil.  In effect, the plants trade the sugars (carbon) to the fungi in return for the minerals the fungi mine from the soil.  The fungi, through their hyphae, extend the plants roots systems much further than the plant can manage.

Building Soil!

The fungi growing through our wood chip mulch is doing the same sort of job.  At the boundary where the surface of the soil and the bottom of the wood chip mulch meet, the fungi are happily at work.  This is where the soil biome, all those billions of microscopic organisms live and work, are decomposing that organic material into forms that the plants can use for nutrients.

wood chip mulch decomposition layers

If you carefully scrape away the wood chip mulch you will notice that the size of the particles and pieces become smaller the deeper you go until all you fine is that wonderful rich, moist material that we all prize, soil rich in organic material.  As you scrape away the mulch, you may notice masses or white cotton material holding the larger pieces of wood chip mulch together.  These are fungi.  Those mushrooms in the mulch are at work, building soil and exchanging nutrients for carbon.

The Carbon Secret

mature wood chip mulch

Carbon?  Did you know that much of the world’s carbon is sequestered in the soil?  Did you know that sequestering carbon in the soil is the quickest and cheapest way to remove carbon dioxide from the atmosphere?  It’s true.  But that is a whole other series of articles waiting to be written, back to fungi.

So I let those mushrooms in the mulch do their job.  I let them mature and release those spores — the more, the merrier. To me, the mushrooms are another indicator that my organic system is working.  The fungi and I are building soil.  I enjoy the beauty of the mushrooms as they push up through the woodchips.  It is another sign of life in my soil.  The more life in the soil, the better, in my view. 

For more information about our organic gardening system visit West Texas Organic Gardening.

There are several articles on our website about fungi, organic gardening, and wood chip mulch. 

The Organic System – Mycorrhizae

Fertile Soil

Wood Chip Mulch

Plus many others and more are added every day.  Please visit our website, join our forums, get on our email list, and like our Facebook page.  You can find us on facebook by searching for @westtexasorganicgardening.