A relatively new class of products in the commercial grounds maintenance industry is the self-propelled spreader and/or sprayer.
 
Some of these machines allow the operator to stand or sit on the machine (Figures 1 and 2); others require the operator to walk behind. Some mount on a zero turning radius mower (Figure 3); others are dedicated machines.

Advantages
The primary advantage of a self-propelled applicator is less operator effort. It is much easier to walk behind a self-propelled applicator than to push a spreader. It is easier yet to ride on a self-propelled applicator. Since the self-propelled applicators don't depend on an operator to push them, they can operate faster, covering more area per day. Offering your crew the opportunity to use self-propelled applicators might allow you to recruit or keep workers who would be unwilling to push a spreader.

Limitations
The cost of a self-propelled spreader or sprayer is much higher than for a non-power walk-behind spreader. One ride-on self-propelled spreader/sprayer costs more than $4,000.

Limits on maneuverability constitute another problem. The self-propelled machines are all bigger than non-power spreaders, so they will be more difficult to maneuver in the close quarters often found in grounds maintenance work. The operating patterns required for a self-propelled machine will likely be different than for a non-powered walk-behind spreader.
 
A typical non-powered spreader can be easily lifted into a truck for transport from site to site; a self-propelled spreader or sprayer will require hauling on a truck or trailer like a riding mower. A large self-propelled machine will potentially cause more turf damage and compaction than a non-powered walk-behind spreader.
 
There may be some days when a non-powered machine could be used without damaging turf while a self-propelled machine could not be used because of wet soil. Speed must be held constant with a self-propelled machine, or rate of application will vary. Maintenance of a self-propelled machine will be far more expensive and time consuming than maintaining a non-powered walk-behind spreader.

Spreader/Sprayer Accessories for zero-turning-radius Mowers
A spreader or sprayer unit that mounts onto a zero-turning-radius mower will be less expensive, but don’t try to mow and apply product at the same time. Rarely will the mower width be the same as the effective swath width for a particular granular product. Even with a boom sprayer, mowing and spraying are not recommended because operating patterns are different.

A self-propelled spreader or sprayer (or combination unit) can potentially reduce the effort required to apply fertilizer or pesticides to lawns, but it comes at a substantial cost and will require some trade-offs in operating mode. If a self-propelled machine is necessary to hire or keep application personnel, it may well be worth the cost.

Note: zero-turning-radius is a registered trademark of Dixon Industries, Inc. The letters zero-turning-radius used in this article do not refer to any particular product shown herein and are used solely as a convenient abbreviation for zero turning radius.