How to Know How Much Weed Killer Is Coming Out of a Hose-End Sprayer?

The amount of herbicide delivered from a hose-end sprayer depends upon the amounts of weed killer and water put into the sprayer and the amount of spray applied on a given area. Rate of spray delivery from the hose-end sprayer can be determined through a calibration process. Many universities have published pamphlets on sprayer calibration and most discuss hose-end sprayers. These pamphlets can usually be obtained from agricultural extension offices. With a few easy steps, you can determine how much weed killer is being applied by your host-end sprayer.

Things You'll Need

• 25-foot measuring tape
• 4 stakes
• Roll of string
• Measuring cup

Instructions

1. Measure out a calibration rectangle on your lawn that is 10 feet wide and 20 feet long, using a 25-foot or longer tape measure. Drive stakes at each corner of the rectangle. Connect the stakes with string to create a 200-square-foot calibration area.

2. Fill the jar on the hose-end sprayer with a measured out quantity of water. Spray the calibration area to the same degree of wetness that you normally spray.

3. Pour the water left in the sprayer jar into a measuring cup and record the measurement. Subtract this number from the original amount of water in the sprayer to find how much water was sprayed. For example, if you sprayed 1 quart of water, that means your hose-end sprayer applies 1 quart of liquid on every 200 square feet -- 5 quarts on every 1,000 square feet.

Tips & Warnings

• The method above determines how much undiluted weed killer is being applied by your hose-end sprayer. If you add water to the weed killer in the sprayer jar, you must determine the ratio of water to chemical. For instance, If you add 12 oz.of water to 6 oz.of weed killer, then half of the solution is chemical. Therefore, you would deliver 1/2 quart (16 oz.) of weed killer to 200 square feet of lawn rather than 1 quart (32 oz.).