Prodiamine 65 WDG Application Calculator
Application Summary
Total Prodiamine (Dry): oz
Metric Weight: grams
Total Water Needed: gallons
Rate per 1k Sq Ft: oz
Understanding Prodiamine Application Rates
Prodiamine (often sold under the brand name Barricade 65 WDG) is one of the most effective pre-emergent herbicides for controlling crabgrass and other annual weeds. However, unlike liquid concentrates, Prodiamine 65 WDG is a "Water Dispersible Granule," meaning you must measure it by weight rather than volume for total accuracy.
How the Calculation Works
The math for applying Prodiamine revolves around converting the "pounds per acre" rate into a "weight per 1,000 square feet" rate. Here is the logic our calculator uses:
- The Acre Constant: There are 43,560 square feet in an acre.
- Ounces per Acre: If you want to apply 1 lb per acre, you are applying 16 ounces per 43,560 sq. ft.
- Ounces per 1,000 sq. ft.: (16 oz / 43.56) = 0.367 oz of product for every 1,000 sq. ft.
Common Rates and Length of Control
The amount of Prodiamine you apply dictates how many months of weed protection you receive. Generally, the breakdown for 65 WDG is:
| Rate (Lbs / Acre) | Months of Control |
|---|---|
| 0.50 lbs/acre | ~3 Months |
| 0.75 lbs/acre | ~4 Months |
| 1.00 lbs/acre | ~5-6 Months |
| 1.50 lbs/acre | ~8+ Months |
Application Guidelines by Grass Type
Every grass species has a "Maximum Annual Rate." You should never exceed this amount in a single calendar year, even if you split your applications between Spring and Fall.
- Bermudagrass & Zoysia: Max rate is roughly 2.3 lbs/acre per year.
- Kentucky Bluegrass & Tall Fescue: Max rate is roughly 1.5 lbs/acre per year.
- Fine Fescue: Max rate is lower, often around 0.75 – 1.0 lbs/acre per year.
Calibration Tip
Water is simply the carrier. Whether you use 1 gallon of water per 1,000 sq. ft. or 2 gallons, the amount of Prodiamine powder remains the same for your area. Always ensure you "water in" the application with at least 0.5 inches of rain or irrigation within 14 days to activate the herbicide barrier in the soil.