This fact sheet is to give people who have, or suspect
they have, a shade problem on their lawn, a method to determine the extent
of the problem and suggest courses of action to correct the problem.
Problems
Typical problems associated with a shade environment compared to grass
grown in full sun are:
- reduced light
- poorer quality of light
- reduced air movement
- higher relative humidity
- prolonged wetness following rainfall or irrigation
- cooler temperatures and reduced temperature fluctuations
- increased disease problems
- moss and algae growth
- competition between trees and grasses for plant nutrients
- competition for moisture, especially from shallow-rooted trees such
as maple or beech
Symptoms
Common symptoms of shade grown turfs are:
- thin, narrow and elongated leaf blades
- reduced rates of leaf appearance
- reduced tillering
- poor wearing ability
- slow recovery after being damaged
- shallow, weak root system
- more succulent turf
Defining Shade
The traditional practice of defining shade as light, medium or heavy,
without attaching a value, is almost useless. Therefore, the following
values are used for purposes of discussion.
Full Sun--100% of the daily available sunlight.
This is the optimum for good turf development.
Light Shade--Less than 100% but more than 75%
of the daily available sunlight reaching a particular area. This range
of sunlight should not present a problem for lawn maintenance.
Medium Shade--Less than 75% but more than 25% of
the daily available sunlight reaching a particular area. This range is
good to fair with the ability to maintain a satisfactory lawn becoming
increasingly more difficult as the total available light diminishes to
25%.
Heavy Shade--Less than 25% of the daily available
sunlight reaching a particular area. It is very difficult to establish
and maintain a lawn at this light level. Choose a more shade-tolerant
ground cover.
Reducing the Shade
It may be possible to establish and maintain a respectable lawn in a shaded
wooded site by removing some trees. Trees should be spaced far enough
apart for good air flow and light penetration. Forty to sixty feet apart
is suggested.
Low branches on trees should be removed to a height of 10 feet or more.
This will allow more early morning and late afternoon light to enter the
area. Thinning the tops of dense trees will allow more light to penetrate
the tops. Thinning is the selective removal of some small and large branches.
Cultural Practices|
Lawn Establishment--Lawn establishment in a
shaded site is more likely to be successful if seeded in early fall (mid-August
through September). The area then has the maximum length of time with
the leaves off the trees. This should allow good root and tiller development.
It is extremely important to continually remove the fallen leaves. Sodding
can be done at this time if the sod contains the correct species of grasses.
Most sods are predominantly Kentucky bluegrass which is not well adapted
to shade.
Once the lawn is established, mow the grass to a height of two to 3 inches.
The longer leaf blade will have a larger surface to gather sunlight. This
will result in a stronger plant.
Fertilizing--Fescues, the dominant grasses in
shade grass mixes, are not tolerant to high levels of nitrogen fertilizer.
Therefore, apply fertilizer only once or twice a year. Limit each application
to one pound of actual nitrogen per 1,000 square feet. The first number
of a fertilizer grade on the bag is the percent nitrogen by weight. For
example, a 10-pound bag of 10-6-4 contains one pound of nitrogen.
If a once-a-year fertilizing program is chosen, apply the proper amount
of fertilizer in late April or October. With the two application programs,
the fertilizer should be applied in late April and early September or
early September and October.
It is important to maintain the proper pH of the soil. Have it tested
every two to three years. The pH is maintained by applying limestone,
and the amount of limestone required is determined by the soil's present
pH and its texture.
Watering--Water only when it is necessary during
prolonged dry periods. Apply one-half to one inch of water, not more than
once a week. Place a few cans in the sprinkler pattern to measure the
water depth. To reduce disease problems, water in the early part of the
day so the grass will dry before nightfall.
Traffic--Limit the amount of traffic and play activity in
the shaded site. This will reduce the damage to the thin-bladed grasses
that are slow to recover.
Compacted Soil--Loosen compacted soils by aerating
or, if the grass needs replanting, till the area to make a good seed bed.
Leaves--Remove leaves every few days as they
are shed by the trees in the fall. A thick carpet of leaves will smother
the weakened grass plants.
Diseases--If fungi become a problem, apply the
correct fungicide at the proper time and rate.
Shade-Tolerant Grasses
The fine-leafed fescues and the newer turf-type tall fescues are the preferred
grasses for dry, shaded sites. Arid, Mustang, Rebel II and Titan are turf-type
tall fescues. In the fine-leafed fescues try SR3000, Reliant and Spartan
which are hard fescues or Jamestown and Victory which are chewings type
fescues. A few varieties of Kentucky bluegrass have shown improved shade
tolerance. These include Adelphi, A-34 Bensun, Baron and Liberty. Where
the shaded site remains wet most of the year the rough bluegrass, Poa
trivialis L. will do better.
Alternate Ground Covers
Sites that do not have at least 25% of the available sunlight should be
planted to another ground cover more tolerant of shade. A few are English
ivy, Hedera helix; Japanese spurge, Pachysandra terminalis; or myrtle,
Vinca minor. By planting an alternate ground cover in the heavily-shaded
site, the homeowner can avoid the annual frustration of replanting grass
seed only to see it die by midsummer.
For pesticide recommendations call the UConn Home
and Garden Education Center at 877-486-6271. |
