Bought a bottle of Just Brand weedkiller from Warehouse yesterday and sprayed on unwanted grass and weeds at about 5pm. Went to look at the grass and weeds today morning and they are still green. How long do I have to wait before I can tell if the weedkiller is working?
I notice that it was raining at about 11pm. Pretty sure it wasn't raining at 8pm. So it only had about 3 hours (maybe 6 hours) of drying time. Is that sufficient or should I spray again?
The label says mix 10ml to 1 litre of water. If I mix 20ml to 1 litre, would it require shorter drying time?
edgecrusherr,
Jan 26, 11:43pm
Can take up to two weeks for you to see anything. As it rained, i suggest trying again if not a large area. Adding a more concentrated mix will not improve the speed or effectiveness - a common misconception!
anne1955,
Jan 27, 12:19am
Hi Be careful I made a stronger brew than that once and made my self sick but at 2 x's you'll be fine lol Yeah old rain can be a bugger for diluting it. Some times we just have to wait. :(
lythande1,
Jan 27, 2:18am
At least a week. After that, if no joy, then you used the wrong stuff on the wrong weed.
ianab,
Jan 27, 2:24am
If it's a Glyphosate (Round-up clone), then nothing seems to happen for 3 or 4 days. The chemcial actually moves around inside the plant, so it kill the whole thing, not just the leaves it lands on.
Give them a week and they will be starting to look pretty sick.
As long as it was on the weeds for an hour or so it will work (assuming it's not something that's resistant to it)
maclad,
Jan 27, 3:11am
Yes if it is glyphosphate it would help to know what weeds you sprayed as so many are resistant to it. But wait at least a week to see if it works. First sign is usually the growing tips yellowing.
dibble35,
Jan 27, 3:34am
I sprayed a Glyphosate (round up clone) on the edges of my paths/driveway maybe 4-5 days ago and it is already obvious where I sprayed - Kikuyu turning yellow. It can take upto 2 weeks in the colder months to show that its working but this time of year in 4 days it should be yellowing - always assuming you sprayed annuals/small weeds and not scrub :-)
piquant,
Jan 27, 4:41am
You basically need to be spraying actively growing weeds for chemicals to work effectively. If what you are spraying is dried out and half dead already you will have little success. Only ever spray to the concentrations recommended on the label and in suitable conditions. It's a case if - if all else fails - read the label!
billyfieldman,
Jan 27, 9:18pm
Thanks. Didn't know it would take almost a week to kill the weeds.
trade4us2,
Jan 27, 10:06pm
I just spray about every four days until the weeds are dead.
eagles9999,
Jan 28, 3:21am
I use Just a lot and using their standard mix ration find it takes 7-8 days to show real signs of weeds dying. have started using it double strength and discovered its usally a couple of days quicker
eagles9999,
Jan 28, 3:23am
piquant. Only ever spray to the concentrations recommended on the label quote wrote: WHY?
brightlights60,
Jan 28, 6:17am
Mrs B here. The most dangerous part of using any form of agri chemicals (weed killers) is in the mixing. Always, always always use at the very least, gloves and a mask and never ever use more than the recommended amounts in the mix. Using too much you will actually do more harm to yourself than what you are trying to poison. The active ingredient in the poison you chose is exactly the same as the active ingredient in Roundup. It is absorbed by the plant and taken down into the root system, so yes, it takes a good 2-3 weeks before you will see the end result. On a hot day you will see the whilt, but leave for a good 2-3 weeks and the plant will be dead. All the info you need on what you are using should be on the label, or attached to the container (its law actually) or you can google the active ingredient.
brightlights60,
Jan 28, 6:18am
This is actually both wasting the weed killer and endangering your own health.
piquant,
Jan 28, 7:36pm
Because all chemicals have to go through extensive trials and registration prior to being available to the public. This involves sometimes years of trialling quantities/mixes in order to get the OPTIMUM results. I think that research scientists are far more qualified to make those judgements than are we - but it seems that there is a large proportion of the populace that thinks otherwise. Using such things as double strengths (in the vain hope that it will work twice as quickly) not only wastes expensive chemicals but (in some cases) can REDUCE the efficacy.
billyfieldman,
Jan 28, 9:53pm
The label says not to store mixed solution in sprayer. Does this mean that any mixed solution left over have to be thrown away? I mixed 4 Litres, have used only about half and kept the remainder in the sprayer, ready-to-use, whenever needed.
pixma,
Jan 28, 11:00pm
I always make up a decent amount, spray everywhere and when I finish there's a bit left in it for next time. Never even crossed my mind to throw the rest out or use it straight away. It is just cheap and nasty glyphosate based stuff. In summer the weeds die within a week max, winter can take 2-3 weeks, especially if it was damp when I sprayed. I think the rain dry time is 6 hours.
piquant,
Jan 28, 11:03pm
That is because the solution will lose efficacy over time AND the possibility that you will forget what is in the sprayer and possibly risk spraying the wrong stuff. It's generally OK if you use stuff within a day or two but you need to learn to only mix what you need. When finished - dispose of any small amounts (not down the drain) and thoroughly wash out both the sprayer AND the nozzles.
pauldw,
Jan 28, 11:26pm
It's good to know that it lasts a day or two, that means the ready to use stuff works ;-)
The mix ratio for Yates Zero as an example varies from 4 to 11ml per litre depending on weed type. Many people could be spraying some of everything in a weedy patch.
The Just brand has 360g/L with which to make 100L mixed solution, giving the recommended 3.6g/L of mixed solution.
That means Yates Zero Rapid ready-to-use is about 4.44 times the strength for the 1 hour visible result.
Wondering whether if for the Just brand, instead of the recommended 10ml per litre of water mix, a 40ml per litre of water mix would give the same result as the Yates Zero Rapid.
lilyfield,
Jan 29, 2:39am
i always do that too, clearly labelled of course. Does not go off
tigra,
Jan 29, 4:03am
Agree you can even use it a week or so later without any loss of efficiency. BUT it is vitally important to LABEL it.
tigra,
Jan 29, 4:05am
Rubbish my health is no more compromised than if I was using the regular strength doseage. ands it does work quicker.
dibble35,
Jan 29, 5:13am
I would agree with this comment ONLY! if you were wearing safety gear and lets face it most of NZ don't bother with appropriate protective gear. so you would be getting a more concentrated dose of the chemical if any sprayed on you.
piquant,
Jan 29, 6:16am
Which only goes to prove my point that a large proportion of the populace NEVER read labels, NEVER think that it might be necessary to use any protective gear, NEVER think anything could, would, should happen to them. The result is that they are the ones that shout the loudest when something goes wrong. Thank god we don't still have Paraquat - there'd be a few dead messageboarders amongst us by now. ALL chemical should be treated with respect. Look at these idiots storing petrol in fizzy drink bottles - it's the same sort of thing.
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