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Adding soap to weed killer

Posted: April 15th, 2010, 9:10 pm
by Wally
I was thinking that some soap or sugar added to the week killer may help it stick to the plants, helping in a better kill.

Am I off the mark?

Also, does hard water make any difference?

Re: Adding soap to weed killer

Posted: April 15th, 2010, 9:15 pm
by andy10917
Dishwashing soap is an excellent homebrew surfacant/sticker. Don't use the antibacterial stuff.

Re: Adding soap to weed killer

Posted: April 15th, 2010, 9:33 pm
by MorpheusPA
Most already have it, so you don't need to add more. I do notice the concentrates tend to be a bit trim.

You really should use a non-ionic surfactant, though--soap is anionic, meaning it carries a negative charge. That can interfere with the weed killer chemistry. Hard water also impacts an anionic surfactant, rendering it less useful (which is why hard water and soap don't get along very well).

If you use the BL Soil Conditioner formula, the yucca extract is a mild non-ionic surfactant. You only need a teaspoon or two per gallon.

Re: Adding soap to weed killer

Posted: April 16th, 2010, 10:01 am
by Dchall_San_Antonio
We really need an article on that BL Soil Conditioner. That way when you refer to it there would be an easy place to go read about it. I have some time. Do you want me to put something together that Morph and Andy can rewrite?

Re: Adding soap to weed killer

Posted: April 16th, 2010, 10:02 am
by MorpheusPA
Sure. Let the word "hyperdeflocculation" be your new friend. :-)

Re: Adding soap to weed killer

Posted: April 16th, 2010, 1:16 pm
by Dchall_San_Antonio
MorpheusPA wrote:Sure. Let the word "hyperdeflocculation" be your new friend. :-)
You better watch your phrasology young man. We have standards here. :club:

Re: Adding soap to weed killer

Posted: April 16th, 2010, 1:27 pm
by MorpheusPA
Dchall_San_Antonio wrote:
MorpheusPA wrote:Sure. Let the word "hyperdeflocculation" be your new friend. :-)
You better watch your phrasology young man. We have standards here. :club:
Oh yeah, oldster? Hyperdeflocculate THIS.

Re: Adding soap to weed killer

Posted: April 16th, 2010, 7:39 pm
by Wally
You know, horse shampoo is an non-ionic surfactant. I use it to clean headstones. I wonder if that would be good to add?

I hope I'm not "nagging" you all for an answer. (I'm sorry, I'm feeling my oats)

Re: Adding soap to weed killer

Posted: April 16th, 2010, 8:03 pm
by andy10917
You really should use a non-ionic surfactant, though--soap is anionic, meaning it carries a negative charge.
The dishwashing stuff I use is Dawn, which contains dimethlyamine oxide, which is non-ionic.

Re: Adding soap to weed killer

Posted: April 16th, 2010, 9:44 pm
by MorpheusPA
andy10917 wrote:
You really should use a non-ionic surfactant, though--soap is anionic, meaning it carries a negative charge.
The dishwashing stuff I use is Dawn, which contains dimethlyamine oxide, which is non-ionic.
I did not know that...I don't use Dawn. Good, that's cheap and effective.

Wally: Yes, that shows good horse-sense. :-) If it's non-ionic, use it at will.

Re: Adding soap to weed killer

Posted: April 17th, 2010, 4:43 pm
by Dchall_San_Antonio
The rumor way back when was that the government bought Dawn to clean up the Exxxon-Valdez oil spill. It probably would have worked except there were not enough ocean waves to emulsify the oil. So the birds were covered in both oil and soap.

Re: Adding soap to weed killer

Posted: April 17th, 2010, 5:01 pm
by MorpheusPA
Dchall_San_Antonio wrote:The rumor way back when was that the government bought Dawn to clean up the Exxxon-Valdez oil spill. It probably would have worked except there were not enough ocean waves to emulsify the oil. So the birds were covered in both oil and soap.
Nowadays, at least, the duck (or whatever) gets washed, dried, and returned to the wild. I don't know what they did back then, but crude oil is heavy, heavy stuff.