St. Augustine is very sensitive turf species and torpedo grass is very hard to treat. We apologize, but we are not aware of a product that will treat torpedo grass and not harm St. Augustine turf. You may want to consider spot treating with RoundUp and then reseed/resod the treated areas.
Unfortunately, we do not have a selective herbicide to kill carpetgrass in another turfgrass. You can use a non-selective herbicide such as RoundUp QuikPro to spot treat the carpetgrass and then reseed or resod as needed in any bare spots.
Roundup QuikPRO does come with a surfactant in the formulation. There is no need to add an additional surfactant.
Unfortunately, most of the herbicides will only suppress the torpedograss for a short time, but will not kill it completely. It is recommended to spot treat the torpedo grass with a non-selective herbicide such as Round Up Quick Pro and then re-seed or re-sod in those areas.
Although atrazine generally is safe to apply to St. Augustine grass, we would not recommend using a product with that active ingredient under shade trees. Most Atrazine product labels advise: "Do not use over rooting area of trees, ornamentals, vegetables or other desirable plants other than the indicated turfgrasses." We would recommend spot-treating with a Roundup-type product, such as Roundup QuikPro, in this type of area.
Each 1.5 oz. pack of Roundup QuikPRO makes 1 gallon of spray solution. For most applications, 1 gallon of mixed product will cover 1,000 square feet.
Unfortunately, there are not a lot of options out there for removing bermuda grass from bahia lawns, as these are very similar grasses. Typically, anything that will kill the bermuda will also harm the bahia. It is usually recommended to spot treat the bermuda as much as possible with a product like Roundup QuikPro, and then replant with bahia in those areas in a couple of weeks when the bermuda is gone.
Yes, Turf Mark Blue can be used with Roundup QuikPRO - 5 x 1.5 oz. packs to make the spray visible when applying
Glyphosate products like Roundup QuikPRO - 5 x 1.5 oz. packs can have a chemical residual in the soil of up to 2 weeks so it is recommended to wait that time before planting in the treated area.