WHAT ABOUT QUICK RELEASE
Quick release forms of nitrogen have an acidifying effect on the
soil and do nothing to stimulate microbial activity in the soil. 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
turfgrasses prefer. Soil test kits are available from your local Penn State
Extension office for a nominal fee. In Allegheny County, consumer
soil test kits cost $12 each, and come with detailed instructions
for taking a good soil sample and information to help you understand
your soil test results. Customers ordering multiple kits at one time
pay $9 each for the additional kits. Send a check made payable to
Penn State Extension to Penn State Extension, 400 North Lexington
Street, Pittsburgh, PA 15208. Write Attn. Soil Test Kit in the lower
left corner of the envelope.
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. Avoid applying fertilizer too early in the spring,
because the lush growth that results is much more susceptible to
disease when we get into hot, humid weather. Liming is best done in
We all know an ugly lawn
when we see one!
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 limetone per thousand square feet, break it into two applications, half in
the fall and half the following spring.
You should also check your lawn for thatch. Thatch is nothing more
than a layer of organic matter between the soil surface and the
crowns of the grass plants that forms as grass plants slough off
dead leaves, stems and roots. Dig up a small square of turf so you
can look at the soil profile. The thatch layer is easily visible. 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 as roots
die when they dry out completely. Thatch is 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 thatch include the variety of grasses in your lawn.
Bluegrass and creeping red fescue are the worst thatch formers of
the cool season grasses. If your soil pH is lower than 6.5, the
microbes that live in the soil and break down thatch are unable to
function. If you overfertilize your lawn, or if you water shallowly
and infrequently, you encourage thatch buildup.
Allowing your grass to grow too long, then cutting it too short and
leaving the long grass lie on the lawn will also contribute to
thatch buildup. If you stick to the one-third rule or use a mulching
mower, the grass clippings are small and break down quickly, and do
not cause thatch to build up.
A moderate 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 detatching job should make you
want to cry when you look at your lawn.
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 again from scratch. 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.
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. If all the
neighborhood kids play in your yard, consider yearly core aeration
in late fall to keep soil compaction to a minimum.
It is good to leave the cores on the soil surface, where they will
break down during winter's freeze-thaw cycles. If the cores are
creating too much of a muddy mess (when children and/or pets play on
the lawn), you can rake them up and put them on the compost pile.
You can also leave them on the lawn and break them up with a rake to
create a seedbed to overseed your entire lawn. Fall overseeding is a
great way to introduce new varieties of grasses to your lawn that
have improved disease, resistance, drought tolerance and/or
aesthetic qualities like color and texture. Once you break up the
soil cores, topdress with a quarter or an inch of compost and rake
it into the soil from the cores.
Then broadcast the seed over the seedbed and rake lightly to barely
cover the seeds. Keep the newly seeded area moist (not sopping wet!)
until the seed germinates.
Growing lawns in the shade
Growing lawns with
Strawberry selection and culture