What does 'gpm' stand for in nozzle specifications?

• A. Gallons Per Minute
• B. Gallons Per Meter
• C. Grams Per Minute
• D. Gallons Per Mile

Answer: (A)

GPM is gallons per minute, the flow rate of spray through the nozzle. This tells you how much liquid is moving past the nozzle each minute, which is crucial for setting the right application rate. When you’re spraying, you’re trying to deliver a target amount of chemical per acre, and that depends on the flow rate, your ground speed, and how many nozzles you have operating. If the GPM is higher, you’ll apply more liquid per unit time, so you either need to move slower, use fewer nozzles, or choose a nozzle with a lower flow rate to hit the label rate. Conversely, a lower GPM means less liquid per minute, so you’d speed up, add more nozzles, or pick a higher-flow nozzle to reach the same rate. A handy rule is that gallons per acre increases proportionally with GPM, all else equal. If you ever need a concrete check, you can estimate gallons per acre with a simple formula that uses GPM, the number of nozzle outlets, your speed in mph, and the nozzle spacing in inches to ensure you're applying the recommended amount.