Rotary spreaders offer the advantages of wide, fast coverage and forgiving patterns, but they are not well suited to working along turf edges – sidewalks, driveways, flower beds, etc.
Because rotary spreader patterns taper out to each side, the operator must either keep the spreader well away from non-turf areas, causing the turf near the non-turn area to receive a very low rate or operate right up next to the turf edge, ensuring a full rate on the turf near the edge but also throwing granules well beyond the edge of the turf.
Spreaders That Address This Problem
At least two major spreader manufacturers have developed professional spreaders that address this problem, and one company now offers a homeowner model. These spreaders use one or both of two methods of pattern control. One method is to block off the metering port area that throws material to the right (Figure 1). Using this method alone reduces the throw of material to the right, but still results in some tapering off of the pattern on the right. It does not cause a sharp cut-off of the pattern. The other method uses a deflector on the right side of the impeller that does effectively result in a sharp demarcation in the pattern (Figure 2). The deflector also causes a peak in the pattern right before the cut-off.
Using both methods on the same spreader gives the best results. Blocking off the metering port area for the right side greatly reduces the material thrown to the right side of the pattern, and the deflector then keeps the granules contained with a sharp cut-off at the right side of the spreader.
In some cases, both blocking the port area and moving the deflector are accomplished by controls on the handles – no need to bend over. On the homeowner spreader, only one lever is required to both block the port area and move the deflector into place, so this spreader is easy to use (Figure 3).
Using a rotary spreader with a pattern cut-off feature will not give results as uniform as can be obtained with a good drop spreader, but it will allow you to take advantage of the good features of a rotary spreader without sacrificing the ability to make an even application right up to the edge of your turf – and no farther.