Assuming you are referring to Trimec Lawn Weed Killer Concentrate The amount of concentrate you mix with water depends on the size of your lawn and the weeds you are targeting. For general weed control, mix 1.5 ounces of concentrate with 1 gallon of water. For larger lawns, you can mix 3 ounces of concentrate with 1 gallon of water. For denser weed growth, you can mix 6 ounces of concentrate with 1 gallon of water. You can also use the Trimec Lawn Weed Killer Concentrate to make a larger batch of weed killer to save for future use. To do this, mix 9 ounces of concentrate with 2.5 gallons of water.