Katana, like most herbicides, does not give a rate per gallon of water but gives an amount per 1000 sqft as it is not the amount of water that is important but making sure you apply the correct amount of product to the area more, Use too much and you risk damaging your lawn, use too little and you will not get adequate results.
Per the product label:
For removal of Poa Annua in warm season grasses you use 0.068 fl oz per 1000 sqft if you are not mixing with Urea or 0.023 to 0.034 fl oz per 1000 sqft if you are.
To decide how much water you want to use, you should mark a 1,000 sq ft area, fill your sprayer with water ONLY, and start walking and spraying just as if you were doing the actual application of herbicide. When you are done walking and spraying the 1,000 sq ft area note how much water it took you to spray that area, and that is the amount you will want to mix the amount of product needed for each 1,000 sq ft area that needs to be treated.
Actual results will depend upon environmental conditions before, during and after application. You will wait at least 4 weeks between applications of Katana Turf Herbicide with a maximum of three applications per year.
Katana Turf Herbicide should not be used on newly sodded grass until it has been established. It is likely established after two mowings. This product should be fine on your four month old zoysiagrass. The amount of product that should be applied depends on what you are treating for. Applications can be made every 4 weeks as needed. Please check the label for specifics.
We would advise waiting 24 hours after an application of Katana Turf Herbicide before watering
Katana Turf Herbicide states that cool season grasses such as Kentucky are sensative to this product. If you lawn is already senstive, it is best to not apply. Since poa annua and cool season grasses are so closely related, there are no real products to remove it that would not also harm the desirable cool season turfgrass. Your only real option would be to spot-treat with a Roundup-type product and then reseed with the desirable grass type in those areas. You can use a pre-emergent like Dimension 2EW in the spring, or Pendulum 2G in the fall if you are not overseeding to help prevent the poa from emerging.
According to the label Katana Turf Herbicide is NOT labled for creeping bent grass lawn and could injure it.
