Prodiamine 65 WDG Pre-Emergent Calculator
Calculate prodiamine 65 WDG dry-flowable pre-emergent for turf and ornamentals from a pounds-per-acre rate, with carrier volume and tank loads.
How This Calculation Works
Prodiamine 65 WDG is a dry flowable, so the label rate is in pounds or ounces of product per acre, not fluid ounces. Convert pounds per acre to ounces per acre by multiplying by 16, then divide by 128 only if you are comparing to a liquid volume. Carrier volume is set by the calibrated GPA and should be enough to move the granules into the soil surface.
Field Calibration & Rate Reference Chart
| Ground speed | Nozzle pressure | Typical GPA | Droplet class |
|---|---|---|---|
| 4 mph | 20 psi | 12 | Coarse |
| 5 mph | 25 psi | 14 | Coarse |
| 6 mph | 30 psi | 15 | Medium |
| 7 mph | 35 psi | 16 | Medium |
| 8 mph | 40 psi | 18 | Medium |
| 9 mph | 45 psi | 19 | Fine |
| 10 mph | 50 psi | 20 | Fine |
| 12 mph | 55 psi | 22 | Fine |
| 14 mph | 60 psi | 24 | Very fine |
| 16 mph | 65 psi | 26 | Very fine |
Common Questions
How much prodiamine 65 WDG do I apply per acre?
Turf rates commonly run 0.5 to 1.5 pounds of product per acre depending on the target weed and soil type. Sandy soils take the lower end and heavier soils the higher end. Always confirm against the label rate table for your grass species.
How much carrier volume does prodiamine need?
Apply in enough water to distribute the product evenly, typically 20 to 40 gallons per acre for turf. Higher volume improves uniformity on uneven ground. Agitate continuously because the dry flowable settles quickly.
When should I apply prodiamine for crabgrass?
Apply before soil temperatures at 4 inches reach 55 degrees Fahrenheit, which is usually several weeks before crabgrass germinates. A split application extends control through the season. Watering in within 3 to 7 days activates the barrier.
Can I overseed after applying prodiamine?
Prodiamine inhibits root development, so overseeding intervals range from about 2 to 4 months depending on the rate. Check the label for the exact interval before seeding. For same-season overseeding, choose a shorter-residual pre-emergent instead.