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RoundUp : Have I overdone it?


LawnSite Member
OK, so I'm working on removing all the weeds from my yard which is A LOT and was suggested I use RoundUp.

So I bought a 1 gallon jug with the pump sprayer and a 16 oz refill thingy as well.

I sprayed the entire back yard (minus the stuff i wanna keep alive of course) and used up the entire jug of spray. after a whole week some of it dies, but MOST OF IT IS STILL ALIVE.

So I stir up some more round up using more than the suggested 6 oz per gallon of concentrated roundup (like 8 or 9) and spray like hell again. (this was last weekend) and now everything is dying exept for this one weed/hellvine/**** thing that is like the terminator. It won't die!

So, on wednesday I fertilized the front lawn with Scott's Weed&Feed and had some left over so I figured "what they hey" and used the rest on the back yard. It was just enough to do the entire back yard... and yesterday I go back there to see how dead things are. and this weed is STILL GOING STRONG.

I went to home depot and bought one of those steal rakes with the teeth and started pulling the dead stuff up. it was not very hard except for the st. augustine that is still there.. I yanked it all up too. But the spots that have this weed that's still alive, is SO HARD to pull up.

What does it take short of setting the yard on fire to kill it?! (not to mention the bits and pieces of st. augustine that won't die either)

But now I'm worried. If I've dumped this much toxins on the yard soil, how long should I need to wait before resoding?

(I live in South florida zones 9 or 10 and the grass I want to use is st. augustine.)

go to a rental shop and ask them for a thatcher. thatching it will do two things for you. 1. it will remove most to all of the st. augie from your yard and 2. it will loosen up the top level of soil which in turn will be benifical to the sod while it tries to take root.


LawnSite Member
Roundup breaks down from the action of sunlight, bacteria, etc...it does not remain in the soil. Though there are those that dispute this. Always follow those label directions and for some tenacious weeds you have to make several applications while the weed is "actively" growing.


LawnSite Member
hicksgroundmgt, I had to look up what a thatcher was! LOL! I had no idea. I've looked around (although not very aggressively) to see who may be renting them out but have not found anyplace yet.

promo, I worked on the yard a bit more this morning and it does seem like it has gotten easier to pull this weed up. I noticed it's little leaves beginning to brown or burn so I'll wait some more and see what happens.

Georgiehopper, Yeah i had read that somewhere about the roundup breaking down but wasn't very sure how accurate that was... any idea how long it's supposed to take before it has broken down?

It maybe a month before I can resod so I think by then it will be safe or safER anyway. We have some more work do to after the ground is ready such as fix a sprinkler head, repair a sprinkler line, but trees back a bit more, etc.

Has anybody used the weezle to de-weedify a yard? I think now it goes by the name of "hedge hog". It's a broomstick with about 3 sets of rotating spikes at the end and you roll it back and forth on the soil. I had been thinking of getting one for this job . At least I know where to find one and it's cheap. :)


LawnSite Silver Member
S.E. Michigan
Originally posted by blackthumb

It maybe a month before I can resod so I think by then it will be safe or safER anyway. We have some more work do to after the ground is ready such as fix a sprinkler head, repair a sprinkler line, but trees back a bit more, etc.

You can reseed the same day after spraying R-up.
Round up is a salt, which becomes inactive once in contact with the soil. There is no residual activity with round up so you can sod or seed right on top of a still wet application with out harming the new plant material.
The reason you are having problems killing a particular noxious weed is due to 2 things: 1. you haven't properly id'd the plant and 2: round up does not work on every plant.


LawnSite Bronze Member
If you have any Roundup left, try putting it in a bucket and using an old paintbrush to apply the Roundup directly to the leaves of the vine. This is a bit more time consuming, but gets the chemical directly on the plant in a heavy application, and you don't have to worry about over spray. "Woody vines" are tough, no matter what chemical you are using.

Also, are you near the ocean? Just in my experience, with absolutely no scientific backing, I have found that Roundup doesn't always work well when used on plants near the ocean. My guess is that the plants may be more salt tolerant, requiring more, heavier applications to get the results you want.

As far as I know, Roundup is a very safe chemical to use. As has been mentioned, you can reseed/replant almost immediately, I believe the instructions say to wait a week.