Mushrooms in the lawn

Tuesday, April 26, 2011

When was the last time you ran into a mushroom expert?  Mushrooms or “toadstools” are reproductive or fruiting structures of some kinds of fungi.  Some fungi do not produce these fruiting, visible structures like common lawn fungus diseases.  Some fungi in lawns are beneficial like endophytes and mycorrhiza.  Most fungi are beneficial because they decompose organic matter which releases nutrients that are then available for plant growth.  What we do not like is the presents of nuisance mushrooms in our beautiful lawns even though they do not damage the grass.

In the soil there are billions of micro-organisms which are constantly working, eating, decomposing elements in the soil.  Fungal fruiting structures release tiny spores that are easily carried in the air to new sites.  These spores find a home and start to grow sending out thin filaments called hyphae.  These hyphae decompose wood, leaves, food waste from compost piles, mulches and organic matter absorbing some for food to live and some develop sufficient fruiting bodies that grow and appear in your lawn.  These fungi can live in your soil for years and when conditions are right, they prosper, such as after periods of prolonged wet weather.  Mushrooms are usually found in areas with poor water drainage and penetration. 

Removing mushrooms from the top of your lawn with a rake or a boot will not kill the underground mycelia from which they are growing, so they are sure to return.  Primarily we remove these mushrooms to keep them away from children and pets curiosity and to improve the lawn’s appearance.  Monitor your lawn and be sure to remove and keep children and pets away from mushrooms in your yard!

Fairy rings are caused by a fungus and get their name from the ancient belief that mushrooms grew in circles where fairies danced.  That sounds great, but we do not like fairy rings in our yard, unless fairies really showed up!  Usually an increase of Jonathan Green fertilizer and irrigation can mask the look for fairy rings in the lawn since the grass grows and fills in better.

To manage mushrooms aeration is necessary to break up the existing dense fungal mat of mycelia.  Remove cores at least ¼” to 1 inch in diameter slightly deeper than the fungal mat.  Determine the depth of this mat with a trowel or shovel.  You may have to aerate these areas a number of times each year to keep ahead of the growing mushrooms.  This aeration breaks up the fungal mat, but also improves water and air penetration into the soil creating a better lawn growing environment.  If the fungal mat is more than say three inches, a shovel or auger may be used to penetrate deeper into the ground.  To completely eradicate mushrooms, you may need to remove the soil to a depth of twelve to eighteen inches.  Refill the trench with fresh soil and reseed the area.  Be careful not to infest any surrounding areas with the contaminated soil!  You also can apply Jonathan Green fertilizer to help the grass to grow and thrive; this fertilization hastens the breakdown of organic matter.  New sod lawn installations require frequent irrigation and sometimes promote the growth of mushrooms.  The mushrooms do not harm the lawn and will disappear when irrigation is reduced.

Some people do not mind a few dandelions or white clover or mushrooms in their lawn.  However, I would rather see them in a meadow field and not my lawn.  Keep the mushrooms to a nice dinner out!

 

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