If you say that's what you do, ... great, then that's what you do. Based strictly on your description and the current price at TSC , that mix of 1 gal of 41% glyphosate and 1 gal of water costs $50. And I have no idea in this world what vassie grass is. So for education, I looked it up and Vaseygrass is an invasive plant native to South America. The Univ of Florida says you guys have it down there. Thankfully we have not seen it (that I know of ) up here in mid-Eastern US. By your numbers you're using 20.5% glyphosate mix. The people in Tallahassee recommend:
https://www.google.com/search?q=How+do+I+get+rid+of+Vasey+grass?&tbm=isch&source=iu&ictx=1&vet=1&fir=zk4TMb0-fCYdZM%2C2yXabloBFaJP6M%2C%2Fm%2F09k4r2p&usg=AI4_-kQbY9y6IE2WC1HEcXGdiaBJZMKSQQ&sa=X&ved=2ahUKEwiZlZ_W_rX4AhVSTd8KHfIUDrsQ9QF6BAhBEAE&biw=1920&bih=969&dpr=1#imgrc=zk4TMb0-fCYdZM
"vaseygrass can be controlled by
spot spraying a one percent glyphosate solution [which is 1.2 ounces of 41% concentrate per gallon.] " Be aware, mowing and tilling can make the problem worse, as the scattering and burying of seeds can exacerbate the infestation. Aug 29, 2019
So... if you are using 1 gal of 41% concentrate mixed with 1 gal of water, that is 20.5%;
that is 20 times the percentage the Univ of FL is suggesting. Granted, wicking may call for a higher concentration than spraying, but that "20 times" might cause some doubts. Especially with the goo costing $135 for 2.5 gal of the 41% concentrate.
https://www.tallahassee.com › home-garden › 2019/08/29