Fall Shade

I took these pictures today, October 26 at 10:30AM on the 5th and 6th greens. The shade in the fall is the worst on both of these greens with the 5th green at least receiving morning sunlight since we removed the trees along the houses but the 6th green receives no sunlight in the morning and only about 50% sunlight until after 11 AM.

5 Green at 10:30AM in October

6 Green at 10:30AM in October

From Dr. Danneberger at Ohio State
Managing bentgrass under golf course conditions is a challenge. Managing creeping bentgrass in
shade under the same conditions is frustrating and may be impossible. Shade not only influences the
amount of light available for plant photosynthesis but also affects light quality.

Plants absorb solar radiation as energy particles called photons. The energy of a photon depends on
the light wavelength from which it originated. Blue, green and red wavelengths provide energy for
photosynthesis. Far red wavelengths help manage plant responses to the environment. Light quality
refers to the proportions of particular wavelengths in the light environment. Changes in the
proportion of red and far red – and possibly blue – light trigger plant responses that affect plant
health.

In shade, a greater proportion of the light present is in blue and far-red wavelengths. These excesses
in blue and far-red light and a deficiency in red light cause turfgrass plants to produce thin, delicate
leaves and rapid, vertical shoot growth. These plants are usually more succulent and commonly
have a poor root system.

These circumstances and a decline in photosynthesis, combined with frequent low mowing and
nearly constant traffic, make it difficult to maintain healthy creeping bentgrass in golf course shade.
Thin, weakened leaves are easily to damage, but they regenerate slower than healthy plants. When
pressure is applied to succulent plants, cell membranes can rupture.

Turf in shade grows vertically faster, to compete with neighbour plants for light. This is a
disadvantage from an agronomical point of view. Because shoot growth is encouraged in shade,
root systems on shaded turf are shallow and sparse. Turf density is poor, and damaged areas are
slow to recover because stolon growth is poor.