A YEAR-LONG ORGANIC LAWN CARE PLAN
(OR, WHEN TO DO
WHAT FOR YOUR TURFGRASS)
Spring is a great time for lawn care, right? Well, yes and no. Lawn chores, like any other part of
gardening, are best tackled throughout the year. Creating a healthy, attractive lawn involves
following guidelines that will help the lawn crowd out weeds and resist
diseases and insects. The outline below
is specific for the greater
March - Soil Testing: Once the ground thaws in the
spring, the soil pH can be tested. This
is a measure of the relative acidity of the soil. Lawn grasses generally like a pH in the range
of 6.2 to 7.0, which is slightly acidic to neutral. Lime raises the pH, or lessens the acidity,
of the soil. Routinely adding lime to
the lawn is not a good practice, since the pH may be raised too high. Cornell Cooperative Extension offices as well
as some garden centers can test the pH for you, or you can buy a home test kit
that is relatively simple to use.
Another good time to check the pH of the soil (and add lime, if needed)
is in the fall.
April - Early weed management: For
some non-organically managed lawns, chemical pre-emergent herbicides are used
to keep out the crabgrass (and other annual weeds). Since there is
no directly analogous organic solution, good management principles are the best
way to reduce crabgrass infestations. Practices which will create a denser lawn
(i.e., correct pH, proper fertilization, overseeding with high quality seed,
etc.) should be used to try to reduce crabgrass infestation to a tolerable
level. Applications of corn gluten in
the early spring have been touted as a way to reduce crabgrass as well. While this is sometimes true, most
researchers now believe that the corn gluten provides the same benefits as
fertilizer -- it stimulates growth so that the lawn can out-compete the
crabgrass. Hence, corn gluten may only
be an expensive form of fertilizer.
Late May - Fertilizer:
High maintenance lawns are
often fertilized three times a year on or around three holiday dates: Memorial
Day, Labor Day, and just after Halloween.
For medium maintenance lawns, fertilizer can be applied at the Memorial
and Labor Day times, and for low maintenance, just once at Labor Day. Each application generally supplies one pound
of nitrogen per one thousand square feet.
Using a slow-release, organic-type fertilizer will provide nutrients
over several weeks, and reduce the chance of fertilizer leaching into
groundwater or burning the turfgrass foliage.
Organic fertilizers "feed the soil" as well as benefiting the
lawn, and have been shown to increase the populations of microbes and
earthworms in some cases. Certain
organic fertilizers can also decrease the incidence of turfgrass diseases. Organic fertilizers tend to be more expensive
than synthetic fertilizers. Often, more
material is needed to apply the same amount of nutrients, since organic
fertilizers are generally lower in nutrient content. In the Capital District, organic fertilizers
are harder to find in stores, since the demand is higher for synthetic
fertilizers.
Summer - Watering:
Lawns generally need one inch
of water per week to remain growing through the summer. This can be supplied in the form of rainfall
or irrigation, so if consistent rainfall occurs, make sure to reduce the amount
of water applied by automatic sprinklers.
Watering in the early morning hours is best, since
the
rising sun will dry the leaf blades and reduce the chances of disease. Providing one inch of water in two or three waterings per week is better than watering a little each
day. If left unwatered,
many types of turfgrass will turn brown but remain alive for several weeks.
There is nothing wrong with letting your grass go dormant during a
short summer drought! This dormancy
period does not harm the turfgrass unless the dry period becomes
prolonged. At that point, the lawn may
be weakened, and then insects and weeds will have a much better chance of invading
and compromising the lawn. Some types of
turfgrass, including the fine fescues, are more drought tolerant than others
and are good choices for unirrigated lawns.
Summer - Mowing:
Not many people get excited
about mowing the lawn, but there are a couple of important considerations. Dull lawnmower blades provide jagged cuts to
the leaves of grasses and give the lawn a brownish cast, so sharp blades are a
must. Mowing the lawn to a height of two
and one half to three inches tall is better than keeping the lawn very short,
since the taller plants will grow deeper roots and compete with weeds more
effectively. If a mulching mower is
used, or the lawn is mowed frequently, leaving the grass clippings on the lawn
can reduce the need for nitrogen fertiliizer by up to
30%, as well as reducing the amount of organic material which ends up in a
landfill or incinerator.
Mid-August - Seeding, Overseeding and Renovation: If
you are seeding a new lawn, renovating an old one, or fixing patches, late
summer and early fall are the best times for these jobs. Warm days, even soil moisture, and less weed
competition increase the chances of establishing a good lawn. In our area, most seeding should be done by
mid-September, since adequate time is needed for germination and growth before
the weather cools further. Sodding, on
the other hand, can be done from March into November if adequate irrigation is
provided. If seeding, buy only high-quality
seed. Avoid seed mixes with annual
ryegrass, which will die after one season, and examine seed labels carefully
for low weed seed content and high germination rates.
Mid-August through much of September is also a good time to core aerate lawns that have thatch and/or compaction
problems. Core aeration is a process where
cores of soil are taken from the lawn and deposited on the surface. The holes created in the lawn allow for
increased air and water penetration.
Overseeding (sowing seed into an existing lawn) can follow core aeration
to increase the density of the lawn.
Late August through September - Grubs: Grub eggs
hatch at this time of year, so carefully cutting a section of lawn and
examining the roots will indicate if young grubs are present. Most lawns do not
always have high numbers of grubs each season. Many lawns are treated with
insecticide needlessly because there are few or no grubs present. Fewer than five grubs per square foot indicates a low population that will cause little damage,
but finding higher numbers may be reason for concern.
There are two biological controls for white grubs in lawns. Milky spore (Bacillus popilliae)
is a bacteria which can be spread on the lawn which
will control Japanese beetles.
Unfortunately, it takes years to build up to sufficient levels in cold
Mid-August into October - Broadleaf Weed Management:
Unfortunately, there are no organic ways to directly control broadleaf
lawn weeds (including plantain, ground ivy, and dandelion) other than
hand-pulling. The homeowner must
therefore provide optimal growing conditions (i.e., fertilizer, pH, water,
etc.) in order to help the lawn crowd out weeds.
November: Relax
- Hopefully, your efforts have created a dense, healthy lawn. After your post Halloween fertilizer
application, you can take a well-deserved break from lawn care!
Detailed information about any of the lawn care tasks above can be obtained
from Cornell Cooperative Extension of Rensselaer County (phone 272-4210).
Fact sheet 7.531
3/01 Written by David Chinery, Cornell Cooperative Extension of