Service Bulletin

Page 1 of 2
Customer Bulletin
Commercial Products
Rotaries #01-04
Product Performance When Cutting Turf
Product: Groundsmaster® 7200 Series June 26, 2009
Affected Units:
Groundsmaster 7200 & 7210 series
Models:
All
Serial Numbers:
All
Information:
The Groundsmaster 7200 series mowers are high performance, versatile commercial duty
products. In an effort to provide the best after-cut appearance (ACA) in the widest variety of
different turf types, the cutting decks have been designed to perform best when cutting grass
that is no higher than 9” (23 cm) in pre-cut height. This would be within normal and accepted
agronomic mowing practices.
Normal and accepted agronomic mowing practices recommended by turf experts are described
as a cutting event that removes no more than 1/3 of the grass blade per event. This is referred
to as the “1/3 rule” and is the maximum amount of grass blade material that should be removed
(per event) while still providing the plant enough tissue left to properly photosynthesize for
regeneration. Removing more blade material than this can adversely affect the plant’s ability to
recover after mowing.
Using the normal and accepted agronomic mowing parameters (1/3 rule) as design criteria, the
cutting decks are designed to process this amount of cut grass material produced at the desired
height-of-cut and to disperse it properly to provide an acceptable after-cut appearance. Keep in
mind that as the desired height-of-cut (HOC) gets shorter, the turf tends to become more dense.
The actual volume of cut grass then increases (per cutting event) at lower HOC’s. If the 1/3 rule
is not followed, after-cut appearance issues can become more prevalent.
In summary, if the1/3 rule is not followed
, turf regeneration, after cut appearance
and safety are all compromised. Attempting to cut long grass down to short
heights (in
wet or dry conditions) will accelerate component wear, inhibit the turf
grasses
' ability to recover and produce excessive chaff discharge that can
accumulate
in the engine compartment and contact hot components which can
ignite a fire.
Optional Blade Configurations and Their Intended Use:
Since cutting conditions vary, Toro offers two additional blade options for these decks to
increase the machine
's adaptability and safety and enhance the performance and/or operator
comfort. Each style of
Toro blade is designed to meet our safety standards and provide
specific characteristics dependent on conditions:
Atomic Blades:
These blades have serrated sail edges that are designed to finely chop dry leaf
material during the fall season. Dried leaves impact the additional serrations at high velocity
and break apart into small pieces. The small dried material is then redistributed into the turf
canopy, providing nutrients and minimizing clean-up. It should be noted that these blades are
designed to mulch dried material and not fresh cut turf grasses.
Flat Sail Blades:
These blades have no sail on them and, therefore, do not generate lift (suction)
or promote under deck
air flow. These blades are designed to be utilized in dry, sparse cutting
conditions where dust an
d airborne debris is a concern at the higher HOC settings.