To determine how long you have to run your sprinkler or
take a flat-bottomed container such as a coffee can and mark off
half-inch increments. Place the can or cans where it will be hit by
the water, and time how long it takes to gather one-half inch of
water. Then run your sprinkler twice as long. You may need to apply
water even slower to steep slopes to avoid wasting water to runoff.
It is best to water in the morning. If you water during the heat of
the day, too much water is lost to evaporation. If you water at
night, the grass stays wet too long, and may be more likely to have
Allowing your lawn to go dormant during hot, dry
weather is always an option. An otherwise healthy lawn can go about
six weeks without rain; it will turn brown, but should recover when
cooler temperatures and rain return.
will help you design a fertilization program that provides what
your lawn needs for optimum health and growth. Inadequate or
excessive fertilization can limit turf growth. It will also tell you
what you have to do to get your soil pH (acidity or alkalinity) into
the optimum range of 6.5 to 7.0 that most lawn grasses prefer. Soil
test kits are available from your local Penn State Cooperative
Extension office for a nominal fee.
'Windows' for Lawns
Typically, late spring (mid- to late May), late summer (late August
to mid-September) and late fall (mid-November) are the best times to
apply fertilizer. Liming is best done in fall. Limestone moves
through the soil very slowly and takes time to effect the desired
change in pH. If your soil test reveals that your lawn needs 100
pounds or more of limestone per thousand square feet, break it into
two applications, fall and spring.
You should also check your lawn for thatch. Older lawns often suffer
from a deep thatch layer. Thatch is nothing more than a layer of
organic matter between the soil surface and the crowns of the grass
plants. Dig up a small square of turf so you can look at the soil
profile. The thatch layer is easily visible. Thatch is created when
growing turfgrass sloughs off dead stems and roots. A thin layer of
thatch - one-half inch or less - is desirable. It acts as a mulch,
moderating soil temperature and maintaining soil moisture. More than
that creates problems, though.
A thick layer of thatch can keep water from reaching the soil, so
your lawn is constantly drought-stressed. And that creates more
thatch. Thatch can also be a breeding ground for insect and disease
problems. Even worse, if your lawn does develop a problem with white
grubs (soil dwelling-insects that feed on turf roots), a thick
thatch layer can make it very difficult to get an insecticide down
to where the grubs are feeding.
The causes of
• The variety
of grasses in your lawn. Bluegrass and creeping red fescue are the
worst thatch formers of the cool season lawn grasses.
• A soil pH
lower than 6.5 immobilizes the microbes that break down thatch.
Over-fertilizing your lawn.
grass to grow too tall, and then cutting it and not collecting the
layer of thatch -
between one-half and one inch - can be removed by dethatching your
lawn with a power dethatcher. Dethatching is very stressful and
should only be done in fall. You can rent dethatchers, or hire a
lawn service to do it for you. Run the dethatcher in one direction,
and then go over you your lawn in the perpendicular direction. A
good dethatching job should make you want to cry when you look at
your lawn. Topdress the lawn with a thin layer (one-eighth to
one-quarter inch) of good compost, then overseed with varieties of
turfgrass that match your existing lawn to help it recover.
If you have over one inch of thatch, consider a total renovation -
removing your existing lawn and starting over. The knives of most dethatchers will not go deep enough to get through the thatch and
down to the soil, which is important for a good dethatching job. A
good dethatching job is a lot of hard work, but will not be very
effective if you have over an inch of thatch.
If you do not have a thatch problem, but the soil is compacted, rent
a core aerator. Again, they are available from many tool rental
shops, or you can hire a lawn service to do the aerating for you.
You might find neighbors who also want to aerate their lawns and
will share in the cost and labor.
Core aerators pull three to four inch plugs of soil out of the
ground and leave small holes behind. This helps aerate the soil
(yes, roots need air!) and alleviate soil compaction. Fall is ideal
for core aeration, but it can be done in the spring as well. If your
lawn does not have a lot of activity on it, core aeration every
three years or so will keep the soil aerated sufficiently.
Annual Lawn Aeration!
If kids play in your yard, consider
yearly core aeration
in late fall to reduce soil compaction. You can
break up the cores with a rake or allow them to stay on the lawn
where they will break up during winter’s freeze-thaw cycles. If they
are creating too much of a muddy mess (when children and/or pets
play on the lawn), you can rake them up and add them to the compost
with compost after core aeration is a good tool to slowly improve
the quality of the soil under your lawn without tearing it up and
starting over. A lawn is only as good as the underlying soil. A six
to eight-inch base of topsoil that contains a moderate amount of
organic matter is ideal, but few lawns have that luxury.
Lawn weed control