You would see results with Grass Out Max within 10-14 days.
There is an applicaiton ratio for spot treaments on the product label for Grass Out Max (Clethodim Herbicide) as well. You would mix .33 oz - .65 oz. per gallon of water.
Yes, Grass Out Max is labeled to be used in and around asparagus. It will take care of the grass that is growing there, but will not harm the plants themselves.
Herbicides are a lot different than other concentrated products and can be hard to understand at first. The application rate depends on the speed at which you apply the product and the output of your sprayer. The amount of water used to apply Grass Out Max 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 Grass Out Max 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 (0.073- .55 fl. oz./1,000 sq. ft.) for Grass Out from the Recommendations section of this label.
5. To each volume of water used as measured in step 3, add the amount of Grass Out as determined in step 4.
Example: If the sprayer uses 1 gallon of water to cover 1,000 square feet and the desired application rate of Grass Out is .55 fluid oz./1,000 square feet, then you would add .55 fluid ounces of Grass Out to every 1 gallon of water to be used.
Grass Out Max per the product label is for use at the rate of 8 - 16 oz per acre to control goosegrass. So thats 0.18 - 0.36 oz per 1000 sq/ft mixed into the water volume you calculated from the test above. Grass Out Max also requires the use of a Non Ionic Surfactant which you will use at its labeled rates which are normally close to 1-2 teaspoons per gallon of water.
Keep in mind: Grass Out Max should NOT be used on home lawns or any areas where there is desirable turf grass. This is a GRASS killer and is to be used to remove grasses of almost every type from ornamental beds, around flowers and other labeled tolerant areas.