Figure 1. Boom-type sprayer on tractor.

Fertilizers and pesticides can be applied in two physical forms: Liquid and granular. Granular products are applied with a spreader; liquid products are applied with a sprayer.

The Problem
It is generally much easier to apply materials onto turfgrass uniformly and at the correct rate if they are in a granular formulation and applied with a spreader. It is relatively easy for homeowners to spray liquid formulations in the garden or on ornamental plants since it is normally necessary only to “spray to drip.” If the pesticide is mixed to the correct dilution rate, all the user has to do is spray until the plants are thoroughly wetted and spray starts to drip off.
 
Treating a lawn is a different story. Fertilizers and pesticides should be applied to turfgrass uniformly and at the correct rate. Both objectives are almost impossible for an untrained homeowner to accomplish with a pump-up or hose-end sprayer. How do you know how much to apply, and how do you move the sprayer correctly to get uniformity?

How Turf Professionals Do It
Professional lawn applicators can and usually do get the product applied with adequate uniformity and at the correct rate by using only a single hose-end sprayer. How do they do it? Thorough training and many, many hours of experience are necessary.
 
Applying material uniformly and at the correct rate with a single, hand-carried sprayer is a very subjective process. If you have calibrated your pace and swath width along with the sprayer discharge rate, you can get the correct rate, and, if you then move the sprayer in an appropriate arc while maintaining the correct width between swaths, you can get acceptably uniform application. But it all takes skill and experience far beyond the level of most homeowners.

How Farmers Do It
Farmers and professional agricultural spray applicators use an entirely different spray system than most lawn care professionals. Farmers use a boom sprayer, a row of nozzles mounted on a horizontal boom and carried by a tractor or implement (Figure 1). Each nozzle sprays a band, and the bands overlap. The tractor keeps the speed constant. If the operator calibrates his spray rate and dilution with the tractor speed and boom width, he will get the right rate. If the nozzles are correctly spaced, the boom is at the right height, and the overlap between swaths is correct, he will get uniform application. Once the equipment is calibrated, little operator skill is required.

Why the Difference?
It should be obvious that the way farmers do it is easier than the way lawn care service pr

Figure 2. Walk-behind non-powered lawn sprayer.

ofessionals do it. So why do lawn care service professionals use single nozzle sprayers? The primary reason is that they need the versatility of a single nozzle to maneuver around obstacles and treat small lawns. Also, a small enough boom sprayer to fit in most lawns would have too little capacity for efficient use by professionals. Turf professionals on golf courses and large turf areas like parks and sports fields do use boom sprayers because they are treating larger, more open turf areas.

How Can You Do It?
Most homeowners are not aware that small, wheeled, boom-type sprayers are available for use on home lawns (Figure 2). These units are hand-pushed and typically pump the liquid using a hose pump (a series of rollers on a drive wheel that force liquid through a flexible hose). This type of pump provides nearly constant output regardless of speed, thus eliminating the need to carefully maintain a correct travel speed. The liquid is then usually sprayed out through two broadcast nozzles on a boom, although smaller models may use only one wide-pattern nozzle, and some larger models may use more than two nozzles.

The spray rate and correct swath width are determined by the manufacturer. All the operator has to do is dilute the fertilizer or pesticide concentrate to give the correct coverage and maintain the correct swath width.

Calibration/Dilution
The only calibration needed (unless you switch nozzles) is to dilute your concentrate properly. Let’s look at an example. If your sprayer is rated to apply 1 gallon per 1,000 square feet and the label on your bottle of pesticide says to apply at 2 ounces per 1,000 square feet, you simply put 2 ounces of concentrate in each gallon of water in your sprayer tank. If you put 6 gallons in the tank, you add 12 ounces of concentrate and shake the tank to mix it. Then, all you have to do is walk back and forth using the rated swath width.

Cleanup
With any liquid sprayer applying fertilizer or pesticide, you should flush the empty tank and plumbing thoroughly after each use. To flush, add clean water equal to approximately 10 percent of the tank capacity, shake to rinse the tank and spray it out on the lawn. Repeat twice to give a triple rinse, and your system is clean. Be sure to spray out the rinsate on your lawn; don’t just pour it out.

Non-powered wheeled sprayers offer homeowners an easy and relatively inexpensive way to apply the correct rate of fertilizer and pesticides uniformly to home lawns. Using this equipment is almost as simple as making granular applications with a spreader.