Question
I live in LI and saw a few mushrooms over the summer, picked them and that was the end of it. Now that the weather is getting cooler/wetter I am seeing them pop up in several places all over my lawn. (This lawn was put down as sod last summer, don't know if that is relevant). I know I need to cut down on watering but other than that what can I do to get rid of them and to keep them from coming back next year?
Thank you!

Answer
The recurring Mushrooms-in-the-Lawn question.  Must be Mushroom Season.

Never heard of that?  Yes, to every-thing there is a Season, and this is when the Mushrooms start busting out all over.  If you were in France and had the right pigs, you would be Truffle-hunting.  Take a look at this Shiitake Culture website, where they declare, 'Autumn temperatures, fall rains and waning light create the perfect climate that throws mushrooms into high gear. During the fall, it seems mushrooms pop out overnight, but they've been growing and gathering energy to form fruiting bodies for months and, in some cases, for a year or more.'

http://www.prweb.com/releases/shiitake/mushrooms/prweb452992.htm

The Sodding you did this summer/last summer suggests issues that would discourage straight Seeding onto your Soil.  Have you had trouble sustaining a Lawn?  Stumps or Roots from long-gone Trees may not be visible, but their very presence underground will make any Grass there miserable, and may even stop it from growing completely.

Neighbor, the quickest way to take control of these is to rake the Lawn every morning.  Parents do that because they worry that children will pick and eat one.  Some people worry about their pets.  These are not the finger lickin' kind of Mushrooms; we don't want a hungry Dog to chew on one for kicks.  Plus they are just not considered a thing of beauty to be growing in the Lawn the way you might like the sight of White Clover or Chionodoxa in the Spring.

Where did these come from?

Mushrooms show up when you have a lot of organic material.  A Tree that was not completely removed, including the underground roots, is a gourmet meal for Fungi and their blooming Mushrooms.

Fungi are Saprophytes -- and ALWAYS part of the wood decay process.  Mushrooms are their 'flowers' getting ready to multiply.

Any stump and/or roots from a felled Tree are underground.  Being decomposed.  Left to rot naturally, this can go on for decades.  Yes, DECADES.

Here's why.

Cellulose and Wood are some of the biggest, toughest molecules to break down.  Cellulose is a complex carbohydrate that gives form and structure to plants.  It decays under the work of special bacteria that have the right enzymes for digesting these long, scary chains of Glucose.  You need a serious microbes population to break down Cellulose.

Not with Wood.

Wood and Bark are Lignin.  Although Lignin may SEEM to be the same thing as Cellulose, and although both are tough and fibrous, Lignin is as different from Cellulose as Salt is to Pepper.  The ONLY time Lignin can decay is when specialized FUNGI do the breaking down.

You NEED Fungi in the Soil to break down the Stump, or the Roots, or the Organic Matter in your Soil.   Without Fungi, this same Mushrooms problem will still be here 100 years from now.

So anyone who tells you how to get rid of the Mushroom-making Fungi is just prolonging your agony.

I suspect there is something else contributing to the Mushrooms epidemic you are observing.  Possibly your Soil is compacted.  That will retain enough moisture to grow all kinds of Fungi.

Deep grinding of the Stump and removal of all traces of Wood, if you have this in the ground somewhere, would be an important exercise.

Even if you could somehow accelerate this process, it would still take YEARS to finish.  Lignin is very, very tough, and Fungi are very, very patient.  And they like to make Mushrooms.

Fungi do something else.  They make your soil increasingly acidic.  As they digest that Lignin, they produce organic acids to break it down; soil pH drops down, and down, and down.

Quickest fix here: Put down a year's dose of Pelletized Lime to adjust surface soil to preferred Grass pH; then blanket the area with a matching sod.  You should also address any compacted Soil issues; Earthworms and Organic Matter (NOT wood chips) will lighten your Soil.

Any questions on this, please advise.

Your timing happens to be excellent.  For a detailed i.d. of this Mushroom crop, I highly recommend you attend a meeting of the L.I. Mycological Club.  They meet this month at the local Planting Fields/Arboretum.  'Mushrooms of Long Island' is the topic.  Let me know if you attend.