B from Half Moon Bay Ca writes
Monterey Weed Impede (Surflan Herbicide) will remain stable on the soil surface up to 21 days following application. In the absence of timely rainfall, irrigation can be used to activate WEED IMPEDE®. A minimum of one-half (1/2) inch of rain or its equivalent in sprinkler irrigation is necessary to activate WEED IMPEDE®.
The Weed Impede product label does recommend that you use either a handheld sprayer or a backpack sprayer to get even coverage and this would be our recommendation as well. The amount of Weed Impede you will use will vary depending on what weeds you are trying to prevent and what season you are treating in but in general you will need 1-12 fl oz per 1,000 sq ft of area to be treated.
According to the Weed Impede product label:"The amount of water used to apply WEED IMPEDE™ herbicide is not critical, but should be sufficient for uniform coverage of the target area. Calibrate by determining the volume of water required to treat 1,000 square feet. Use this calibration volume to determine the amount of water and WEED IMPEDE™ herbicide needed to treat the target area (see the following calibration example). Note: Sprayer calibration (volume of spray needed to treat 1,000 square feet) will vary with each individual operator.
Steps in Calibration:
1. Mark an area of 1,000 square feet (i.e. 20 by 50 feet or 25 by 40 feet).
2. Place the sprayer on a level surface and add water noting the final level of water in the spray tank.
3. Spray the marked area with a sufficient volume of water to provide uniform coverage. Refill the sprayer to the same level as before measuring the amount of water added. The measured water added to the sprayer is the volume needed to cover 1,000 square feet.
4. Determine the application rate (fl. oz./1,000 sq. ft.) for WEED IMPEDE™ from the Recommendations section of this label.
5. To each volume of water used as measured in step 3, add the amount of WEED IMPEDE™ as determined in step 4.
Example: If the sprayer uses 2 gallons of water to cover 1,000 square feet and the desired application rate of WEED IMPEDE™ is 3 fluid oz./1,000 square feet, then you would add 3 fluid ounces of WEED IMPEDE™ to every 2 gallons of water to be used."
Answer last updated on: 10/30/2022