Smithco Turf Spraying Guide - Manual (Page 10)

for soil applied material, small droplets, which more fully cover plant for foliar applied materials.
Pressure also affects droplet size. More pressure at the same nozzle produces smaller droplets, more
subject to drift. The general rule on pressure is to use the lowest pressure possible with just enough to
form adequate spray nozzle patterns.
Though there are many types and sizes of nozzles, two specific types have proven most successful in
turfgrass management. The first type is target directed. It sprays the material in a direct line downward
to the target turfgrass.
These are flat fan nozzles, commonly referred to as Tee-Jet nozzles. They are available in a wide
variety of sizes for any required discharge volume rate. They are the best for many contact or foliar
applied pesticides. They are spaced either 10" (25 cm) or 20" (51 cm) apart. They overlap one another
by about 1/3.
The second types useful in turf management are broadcast type
nozzles. They are commonly referred to as raindrop or floodjet
nozzles. They spray a hollow-cone shaped pattern of much larger
droplets, which fall quickly to the turf under their own weight. They
are best for systemic pesticides or any material requiring a large
volume of water for soil application.
The larger droplets are not subject to drift from wind and are a safer,
environmentally friendly choice in many situations. The nozzle's third
function is to disperse the material at a specific pattern, which will insure an
even distribution of chemical across the swath covered by the boom.
A graph of the pattern formed by flat fan (tee-jet) nozzles would show most
liquid concentrated at the center, then tapering off where it begins to
overlap with the next nozzle-approximately 1/3.
The pattern of liquid dispersed by the hollow-cone (Raindrop)
is more even across its' width. Each nozzle overlaps the
adjoining nozzle by 100%. That is to say the area covered by
each nozzle extends to the center of the two nozzles on either
side.
In order to properly develop their spray pattern, each nozzle
must be the proper distance from the next nozzle (spacing)
and the proper height above the ground.
SPACING - Turf spray nozzles are normally 10" (25 cm) or
20' (51 cm) apart (some cases 30" / 76 cm), depending on
the type of spray boom and type of area to be sprayed.
Very fine, level areas (golf greens & tees, bowling lawns,
tennis courts, etc.) may be sprayed with nozzles spaced
every 10" (25 cm).
Information from Delavan catalog
on 45° Tilt of Rain-Drop
7