Diluting glyphosate

[Scott]

I managed to obtain concentrated glyphosate on the Internet. The instructions contained vast amounts of detail - pages of it - but I was unable to find any clear statement on whether or how much it should be diluted. I decided to dilute it one part in five.

I think I probably managed to break numerous EU Regulations. The only measuring vessel I could find was a kitchen measuring jug. I had no suitable gloves so I decided to pour carefully. However I got it on my hand, which I doused with water for a bit and on the floor (tiled). I have now washed the jug and rinsed it with boiling water. I'll leave it in water a bit longer and replace the dish cloth. I have also cleaned the floor. If I am no longer posting to uk.d-i-y next week you will know why!

Anyway, does anyone know what the recommended dilution factor is? Is there actually any better weedkiller available? I believe not.

[Tim Streater]

For the 360gm/litre stuff, I use about 25cc in a litre of water. Pretty much what it says on the tin. You can scale appropriately.

[Scott]

Sadly not. I was apprehensive that I would have to read through the

10 pages of product instructions again so I thought I would 'ask a friend' instead. Thankfully the answer was a model of precision.

[Andy Burns]

Waaaay too strong!

Assuming you have 360g/litre glyphosate, and using it in a sprayer, I use use 125ml to 5 litres of water i.e. one part in forty.

[Harry Bloomfield]

Scott presented the following explanation :

Was it Rosate 360?

I bought 5L of the same. As I read it, it needs to be diluted to around

40ml per litre of water for use in a spray. That is around 25:1.

It suggests if not diluted enough, then it will act too quickly and kill the leaves off too quickly and not be drawn down into the roots to kill those off.

At 25:1 applied 6th July and there was no noticeable effect until around the 18th, now all of the weeds sprayed are noticeably dead. Which is about right.

[Mark Allread]

The instructions should give a dilution rate for a knapsack sprayer. Use those for the dilution rate and also try to apply at the recommended coverage rate. Its worth practising first with plain water on a marked area of dry hard surface so you can see where you have applied it to.

You'll be surprised at how far a proper mix/application will go. You should be looking at around 25ml/litre ie 1:40 as the mix rate. Application rate will differ according to what you are trying to kill.

[Kit Jackson]

Most concentrated glyphosate is 360g/litre although stronger is possible. The standard dilution is 100:1. ie 10cc glyphosate concentrate to 1 litre of water. You can use it stronger though it's not necessary but be prepared to wait. It may be 2 to 3 weeks before you see the weeds keeling over. It will kill most things, there's only a few plants that are resistant to it.

[Caecilius]

You need to know the glyphosate concentration. The stuff in garden centres is often a much lower concentration than the stuff you can get a farm shops or online.

360 g/l is the most common concentration for agricultural use, although there's 480 g/l available as well. I've had a 5 litre container of 360 g/l for about 5 years now, and it's still going strong: a little goes a long way.

Assuming you're using 360 g/l:

The concentration depends on what you are using it on. But 100:1 is a good starting point. That's 50 ml in 5 litres. This will kill grasses and general weeds around the garden. It's what I generally use.

40:1 is the next step up, which will kill most of the stubborn stuff.

For really difficult stuff, like things with waxy leaves, you can use

20:1. but I've never had to.

This is assuming you spray as recommended to cover the leaf, but no so much that it starts to drip off.

Make sure you wait at least two weeks before deciding it hasn't worked.

[Mark Allread]

I think it should be t'other way round - 25ml/litre or 1:40 and then watch the application rate.

[Andrew Gabriel]

When it was first released, the manufacturers demonstating drinking glyphosate to show how non-toxic it was (probably well diluted as applied to weeds, not concentrate). That actually back-fired on them, because at the time, farmers thought that if it didn't kill you, it couldn't possibly kill weeds, being more familiar with other much more toxic weedkillers at the time.

Also, there are still many cases per year of people drinking it to commit suicide, only to find it doesn't work.

Of course, you shouldn't deliberately drink it in any case, and you should throroughly wash out any container. (I personally wouldn't use a food container.) The weedkiller contains other things too (usually detergents) to help it absorb into the green parts of plants.

You would have to qualify what you mean by 'better'. There are many potential properties of weedkillers - which ones are you after? Flame throwers and more fun and more instant, but not long lasting.

Mine comes as 490g/l concentrate. For spraying, it suggests diluting this 12-18ml/1L water.

Using too concentrated causes it to kill the leaves where it makes contact, and not get transported into the roots, so the plant just continues growing new foliage.

[Scott]

Well, I can see that argument. I wouldn't be convinced about its toxicity either.

I would agree. It was made of glass, not plastic and my memory of chemistry classes is that glass if very non-absorbent.

I would prefer something instant. I remember using sodium chlorate in a previous garden and within two hours it looked as though the place had been napalmed. I may be showing my age!

I do have a flamethrower which I used today as well. My understanding is that although entertaining they are not very effective.

Glad I asked. I have got it spectacularly wrong. I will re-dilute what is left I which thankfully is most of it). .

[Chris Hogg]

They are fine for shallow-rooted weeds; you don't even need to burn the weed to a cinder, as long as it gets hot enough to cook and burst most of the cells. But it's not very effective against deep-rooted weeds such as dandelions or docks; it'll kill the tops, sure, but the root will then re-sprout and you're back where you started.

[ss]

Is there much difference between Rosate 360 and Rosate 360 TF or are they the same with respect to killing weeds.

[Harry Bloomfield]

ss used his keyboard to write :

Sorry, mine is the TF. The ebay sale suggested that the TF was the same, just a later version of the 360.

[Tim Streater]

I'm not convinced about that. If a jar has had SWMBO marmalade in it, or sandwich spread, or that tasty minced pickle, then I can still smell that in the empty after a number of passes through the d/w.

[Andy Burns]

I think the TF is "tallow free", the EU was making noise about banning glyphosate, or the combination of glyphosate with a tallow based adjuvant ...

[Old Codger]

I use roundup 480 g/l in a sprayer and dilute to the recommendations for roundup 360 g/l. Thus I dilute 20 - 25 ml/l for perennial grasses and

50 ml/l for ivy and other waxy leafed plants. You have to wait at least a couple of weeks to see any effect but it does work well. Although roundup will kill most things I use SBK for nettles, brambles and woody weeds diluted 25 ml/l in a sprayer. For tree stumps paint SBK on the stump diluted 50/50 with water.

[Huge]

There are no other weedkillers available, in essence.

[Jethro_uk]

Maybe a soaking in homebrew sanitiser ?

[pamela]

As a separate question, is it necessary to shake or mix ready-diluted glyphosate?

I bought a spray bottle of ready-to-use glyphosate but the weeds I treated didn't all die off even after a few weeks. I use only a fractio of the contents.

I wonder if the results would be better if I had shaken the bottle first?