Q I have large spots of beige grass in my lawn. It looks dead. What causes this, and what can I do about it?
A It sounds like snow mold. After snow melts, lawns can be covered with small to medium-size, circular, light tan patches of what appears to be dead grass. Sometimes these circular patches will coalesce. This condition is usually caused by fungi that grow and thrive in cold, moist (but not frozen) conditions.
Most of this dead-looking grass is confined to the grass leaves and doesn't affect the actual growing points of the plant. The grass will, literally, outgrow the symptoms. A light raking to lift up the grass foliage will speed recovery and stimulate growth. There is no need for fungicide at this time of year.
Narrow bands of dead grass adjacent to hard surfaces typically indicate the grass has been affected by deicing salts used on streets, driveways and sidewalks. Sometimes there will be large dead areas next to the ends of sidewalks or driveways where snow from the street and/or driveway was piled. After a few spring rains or a couple of thorough soakings from a garden hose, these areas can usually be repaired by seeding or sodding.
There are grass seed mixtures that contain a more salt-tolerant grass known as Puccinellia distans, along with other traditional lawn grasses known to be relatively salt-tolerant. Two of the more common varieties of Puccinellia distans are Fults and Salty. They will usually be listed on the container seed label. The mixtures are often sold for boulevards or other areas that are exposed to deicing salts.
Repair seeding can usually be done as soon as the soil has dried out somewhat and is no longer muddy and soft underfoot. Be sure to lightly loosen the soil surface so seeds can easily be incorporated into it. You can also use prepackaged "mulches" for additional protection in the newly seeded area. Follow package directions for proper use of the particular product.
BOB MUGAAS, TURF GRASS EDUCATOR, UNIVERSITY OF MINNESOTA EXTENSION
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