Figure 1. Trigger sprayer.

Whether you have a few rose bushes beside your house or a half-acre garden, you will need a sprayer to take care of your plants.

If you are an organic gardener, you will need to spray biological control products. If you are a conventional gardener, you will need to spray pesticides. Many types of sprayers are available to you.

Trigger Sprayers
The least expensive option for small spraying jobs is a small hand-carried plastic bottle with a hand trigger pump (Figure 1). A sprayer of this type is adequate for treating a few small patio plants or spot spraying herbicide around a small lot. On some models, the spray pattern is adjustable. With this type of sprayer, you place a diluted solution or suspension into the bottle. If using suspended material, you will need to shake the bottle often to keep the material suspended.

Hose-end Sprayers
Another inexpensive option for home lawn and garden use is a hose-end sprayer. These devices consist of a bottle with a venturi suction device, and they screw onto a garden hose. These sprayers mix the pesticide in the bottle with water while spraying, thus diluting the material as it is sprayed. With this type of sprayer, the directions may tell you to place concentrated pesticide into the bottle or to partially dilute the material in the bottle, depending on the dilution ratio of the sprayer and the concentration needed. The spray pattern and the dilution ratio may or may not be adjustable.
 
It is important to follow both the sprayer manufacturer’s directions for use and the pesticide label instructions for dilution. Even so, the actual dilution applied may differ substantially from what is claimed by the manufacturer. If using suspended material, you will need to shake the bottle often to keep the material suspended.

Hand-carried Pump-up Sprayers
The next step up is a 1- to 3-gallon hand-carried pump-up sprayer (Figure 2). Most are plastic, although steel and stainless steel models may be available. With this type of sprayer, you dilute the pesticide to the correct strength in the tank. You then install the

Figure 2. Hand-carried pump-up sprayer.

lid and pump the sprayer to pressurize the tank. You will need to repressurize the tank several times as you work, because the air volume in the tank changes and causes a pressure drop as the tank empties.
 
If using suspended material, you will need to shake the tank often to keep the material suspended. The spray pattern is usually adjustable by twisting the nozzle. You can spray a lot of plants with even a 1–gallon tank.

Lever-pump Backpack Sprayers
The biggest, best, and most expensive hand-powered sprayers are lever-pump backpack sprayers (Figure 3). You wear these sprayers like a backpack. The tank typically holds from 1 to 5 gallons of diluted spray mix. You hold the wand on the end of a hose in one hand, and, with the other hand, you pump a lever to pressurize a small internal chamber. On some models, pumping the lever also actuates an agitator to keep the pesticide in suspension. Some sprayers use standard agricultural nozzles and thus allow you to interchange nozzles and obtain many different spray patterns and spray rates.

The type of sprayer you need will be determined by the amount of spraying you need to do. Any of the above sprayers except the hose-end sprayer should do an adequate job if used properly. Some hose-end sprayers will not deliver the correct concentration and are not recommended.

With any sprayer, it is i

Figure 3. Lever-pump backpack sprayer.

mportant to avoid contamination. A few drops of herbicide left in a sprayer can cause a real problem when you spray insecticide or fungicide on the roses or tomatoes. You need to rinse your sprayer thoroughly at least three times after each use, including pumping clean rinse water through the hose and nozzle.
 
It is not enough to just rinse the tank or bottle. If you do much spraying, it is a good idea to have separate sprayers: one for herbicides and one for insecticides and fungicides. Even with separate sprayers, you should rinse your sprayer unless you use only one chemical in it.

With one exception, you should not leave any pesticides stored in your sprayer. Glyphosate (Roundup®) is one of the few pesticides that is water soluble and can be stored in diluted form without degradation.