1 July 2009
In The Garden With the Fluvanna Master Gardeners
By Irene C. Burke - Fluvanna Master Gardener
Fluvanna County Extension Office: 434.591.1950
Mushrooms in the lawn evoke a range of responses from gardeners. Some who value lush green turf find them an intrusion, some find them a curious and transient feature, which they usually are, and some find them an asset, which they can be.
There are a few reliable resolutions to this dilemma for all these gardeners, some low care, some monumental, depending on the mushroom and the gardener.
What are mushrooms and why are they in the garden or the lawn? When mushrooms rise you are seeing the fruiting bodies of fungi, the periscopes of threads gliding through the soil. These white-netted strands found in the earth, found beneath mulch and matted leaves, transport nutrients and birth mushrooms.
When conditions are right, after extended wet weather, fungal strands produce their "fruit" or mushroom. The mushroom lives on death and decay; its underlying fibers hastening organic matter-leaves, wood, and tree bark-to their final resting state, humus. And as the rot proceeds, a fungus filaments absorb nutrients for themselves while sharing nitrogen with neighboring roots.
Fungi may live in the soil for years before fruiting. When all things come together, they send up the mushroom with spore-filled gills. As you thread your own way through the garden, you and the wind scatter the spores to begin a new generation of fungi.
A word of caution-never eat wild mushrooms unless you are an expert in these matters. They could be poisonous. Remove these capped ornaments as soon as they appear if children or pets are expected to roam the yard.
When fairy ring fungi appear as an arc or circle of mushrooms or sometimes as dark green grass, rake off or hand pull the offenders to the compost pile, being careful to wear gloves and protective clothing. For cosmetic treatment of the green ring lightly apply a 6-2-0 fertilizer, apart from that, do nothing.
As the curve moves further out with resulting turf die-off in the center, there are two courses of action: deep core aeration to break up the thickly matted filaments or replacement of the sod and soil to a depth of 18". Thats monumental. Dont let it get to that.
To improve oxygen and water penetration, aerate the lawn seasonally to a depth of at least 3" with " to 1" diameter cores.
Beneficial mycorrhizae fungi sometimes erupt in mushrooms and are vital to the health of beeches, birches, firs, oaks and pines as well as other woody plants and shrubs. Under your gardens surface some 80% of the roots connect to mycorrhizae fungi for mutual benefit.
The Amanita or Death cap mushroom as well as truffles are examples of mycorrhizae fungi. Unless there is danger of a child or pet eating these mushrooms, leave them where they are.
Mushrooms are an indicator of decaying organic matter, a good thing in your garden. Welcome them with great respect.
Tip of the Week
Connect with experts at Virginia Tech via your iPod or MP3. For a download, search the Web site: http://www.weblogs.cals.vt.edu/turf_garden/about/ Learn all about your lawn, while pulling those noxious weeds, hoeing that row or harvesting your luscious tomatoes. No iPod or MP3? Download a PDF file equivalent from the same Web site.