Can too much
green be bad?
Three soil conditions determine the
green color of your turf: nitrogen,
sulfur, and iron (manganese plays a minor role). For most turfgrasses, the
"ultimate" dark green color is achieved with nitrogen
fertilizer. Yet, excessive nitrogen can carry a heavy price—in added
fertilizer costs and potential damage to your lawn.
Water stress. Excessive
nitrogen
causes higher evapotranspiration rates (the rate at which
your lawn gives up its moisture to the air). This uses up
the water around the roots faster, and means you have to
water
more frequently.
Disease. Excessive nitrogen
accentuates the effects of disease and insect injury to
grass plants.
Root die-back. Too much
nitrogen can
cause roots to die back and decrease in size and number.
Reduced recovery from stress. Too
much fertilizer exhausts the plants' carbohydrate
reserves, reducing the turf's resilience to endure heat, drought, cold, and
winter desiccation (drying).
How much fertilizer is too much?
The nitrogen level at which negative effects occur depends
on the turfgrass species and cultivar, soil texture, amount
and frequency of rain and irrigation, and whether grass
clippings are removed or left on the turfgrass. As a
rule-of-thumb, fertilization rates greater than 1 pound of
actual nitrogen per 1,000 sq. ft. per application exhaust grassplant carbohydrates.
