Scalping on slopes or on uneven terrain, mowing too short, and filling the mower with fuel
on the lawn can cause brown areas. Be aware of slopes and depressions in the lawn and mow
accordingly. Change mowing direction about every other mowing to avoid scalping.
Fill mowers with fuel on driveways or other hard surfaces to avoid spills in the
lawn. In spring, a mowing height of about 2 - 2 1/2" is good for a
blue grass - perennial rye mixture. In summer, a mowing height of 3-4"
will help keep grass roots shaded and to help keep down stress.
Fertilizer mis-application or spill
Misapplying fertilizer, filling the spreader on the lawn, and fertilizer spills
can all cause brown areas. Fill spreaders on the driveway or other hard surfaces and
clean up spills. Make sure the spreader is calibrated correctly and is being used properly
by making header strips and shutting of the spreader on turns.
Follow label directions whenever applying herbicides to or near a lawn.
Non-selective herbicides such as Round-Up or Finale can be misused and/or accidentally
sprayed on lawns, causing brown areas. Applicators sometimes make the mistake of
stepping in the treated area, then onto the lawn, leaving behind a trail of footprints
that later turn brown.
Poor and/or Compacted Soil
If soil is so poor that roots can't penetrate and fail to establish, brown areas
may appear while the neighbors' lawns look fine. Soil in areas frequently
trafficked, such as footprints or animal paths, can become compacted and lead to a decline
in lawn quality.
Lack of rainfall or irrigation can cause Kentucky bluegrass and perennial
ryegrass lawns to go into a dormant state. South facing lawns and slopes may begin
to turn brown before other parts of the lawn from exposure. These lawns can survive
drought periods for a few weeks with intermittent rainfall. Note: drought-stressed
lawns are more susceptible to mechanical and heat damage. To
properly water a lawn, apply the equivalent of 1" of rainfall per week and
water in the early morning so the turf has a chance to dry off by night
fall. Avoid frequent shallow waterings.
Buried Construction Debris
Buried block, siding, plywood, etc. can all cause dry areas where grass roots
can't absorb sufficient moisture. Unfortunately, in newer construction, buried
debris is common. If you can't determine a cause for browning, do some digging to
investigate what is below the brown area.
Competition with Trees and Shrubs
Woody plants compete with lawns for water, nutrients, and light. Plants
with shallow roots may out-compete the lawn in hot, dry seasons. Deep, supplemental
irrigation in some areas may be needed to avoid lawn browning.
Dog urine can be high in salt content and cause injury to lawns, especially if
the soil is dry and infertile. A dark green ring of grass can surround the spot,
related to nitrogen contained in the urine. Heavy watering reduces the salts to a
less toxic concentration. An application of Gypsum to the area will
help to neutralize the urine salts.
Insects and Disease
The common lawn insects and disease can cause various patterns of dicoloration
and browning. Become aware of the signs to look for and the time of year that they
are active in order to diagnose them accurately. Correct diagnosis
is essential for treatment which may include the use of fungicides and/or
insecticides as well as cultural methods of control.
In wet years, pythium can be a problem in which the crown rots away.
Rhizoctonia, or brown patch, acts as a "dry rot" in hot weather.
The problems in the lawn look quite similar but the treatments are