Dawn on my lawn?

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Blackbird
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Dawn on my lawn?

Post by Blackbird » March 7th, 2011, 3:00 pm

I've been reading about the practice of spraying Dawn on a lawn and the many benefits that come along with doing that. Wouldn't that be detrimental to the earthworms in your lawn? I thought it irritated them. Since they drag organic matter into their burrows, so they can feed on the material later, wouldn't the the soap film that's on that debris harm, or kill them when they eat the debris later?
I just wanted some clarification on this. I know soap affects lawn-damaging insects this way when they try to eat grass in your lawn.

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Dchall_San_Antonio
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Re: Dawn on my lawn?

Post by Dchall_San_Antonio » March 7th, 2011, 3:19 pm

That is a good question. As background for someone who did not find the lengthy discussion which you found, I'll try to summarize. We have much discussion here about spraying surfactant materials which reduce the surface tension of water. The purpose is to let the water drain deeper into the soil and hopefully remain there long enough to create a better environment for the beneficial soil fungi to spread. More beneficial fungi means softer soil. Thus the spraying of surfactants would be an easy substitute for the more difficult practice of mechanical core aerating. We also think softer soil equates to better turf, but I don't think I've ever seen anything about that.* In the discussions there is talk about using organic surfactants (yucca extract) and synthetic surfactants (man made soap and detergents). My preference is to use generic baby shampoo while there is some discussion about using Dawn dish washing detergent. With that in mind...

...is Dawn good, bad, or indifferent to the worms and other beneficial critters in the soil?
I'm not going to answer right now, I'm just setting up the background for why someone might spray Dawn on a lawn.


*Similarly I've never read any real science to say that plowing a field is a good thing to do, but people have been plowing for 60,000 years...so it must be good!!

Bra
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Re: Dawn on my lawn?

Post by Bra » March 7th, 2011, 3:57 pm

This would be the non antibacterial Dawn if I've retained any of what I've read.

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MorpheusPA
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Re: Dawn on my lawn?

Post by MorpheusPA » March 7th, 2011, 7:01 pm

I was expecting sunrise photos. You have disappointed me for the last time, Blackbird. (points to anybody who gets the reference, it's an easy one)

If you put a worm into pure Dawn, you're going to have a very unhappy worm. Very quickly, you'll have a dead worm. The soap dissolves the mucus coating on the worm, rendering it wide-open to infection, chemical changes from the alkalines, and negative osmotic pressure into the Dawn (the worm dries out, in other words, very fast).

Of course, if you put a plant in pure Miracle Gro, you end up with a dead plant. Too much is not a good thing in either case.

At the amounts we use, ounces per thousand square feet, the impact is minimal. I've used heavier surfactants than Dawn for years (sodium laurel sulfate, sodium laureth sulfate, and the like) with absolutely no impact to the worm population, which is in the quarter million range on 9,000 square feet (7K lawn, 2 K gardens).

Oddly, aphids (and many other insects) don't like even slightly soapy water in the slightest. I'm careful not to spray plants in the garden for that reason--I have few aphids, and plenty of predators. I want to keep the predators around, so they need things to hunt.

Blackbird
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Re: Dawn on my lawn?

Post by Blackbird » March 8th, 2011, 12:55 pm

That's good info to have Dave and Morph. After seeing Jerry Baker recommend liquid soap applications so fervently, I figured there had to be something to it. I just wanted to make sure he hadn't fallen off his rocker when he recommended doing those apps.

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cactus
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Re: Dawn on my lawn?

Post by cactus » March 8th, 2011, 3:49 pm

Blackbird wrote:After seeing Jerry Baker recommend liquid soap applications so fervently, I figured there had to be something to it. I just wanted to make sure he hadn't fallen off his rocker when he recommended doing those apps.
I'd take Mr. Baker with a grain of salt (and a can of flat cola, 3 tablespoons of mouthwash, 1 teaspoon of cider vinegar and anything else he recommends in his tonics). Most of the ingredients seem to have a reason for being there, but the quantities/dilutions he recommends for turf applications have never made much sense to me. And using golf shoes to aerate the lawn...?

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MorpheusPA
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Re: Dawn on my lawn?

Post by MorpheusPA » March 8th, 2011, 4:04 pm

+1 Cactus. I didn't want to say it. Baker's a collection of anecdotal formulae that people have said help the lawn. People also feel better on sugar pills if you tell them they're placebomyacin, so I take that with a grain of salt myself.

Many clearly can't work, don't work for the reason (if any) given, and contain items that don't make any sense given the title of the formula.

You remember the statement "It takes a village?" In this case, it takes a chemist. :-) At least a hobbyist.

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