Well, surfactants (detergents) make water wetter & allow it to "seep" or flow into all the tiny places much more readily. It also tends to negate the effect of how Fe-containing molecules form on organic surfaces, which turns soils hydrophobic (water-repellent) as they dry to below about 30% moisture content.

Maybe it's just me, but I think that a 1:128 solution of H2O:detergent sounds pretty concentrated for use as either a topical or root drench. There are organic compounds in roots (oils eg) that are readily broken down by detergents, which I cannot imagine to be a good thing. A better strategy is to use a porous soil & water frequently enough to prevent a drop below 30% soil moisture and forgo the detergent.

Al

Thanks, Al, I will take your advice...sounds a lot safer, not to mention saner!!

Anyone know if true soap (rather than detergent) would work similarly? I use a bit of Dr. Bronner's Magic Soap, which is a natural liquid castile (i.e. vegetable oil based) soap in my misting water to deter insects, and I have watered with it before to get rid of fungus gnats. So would this type of soap "make water wetter"?

A cheeper way is to save all those little bits of hand and or bath soap and crush them down, and add them to a covered bucket 2/3 way filled with water. The soap will desolve in time, unless you help it along. Add water or soap to get it to look like old ivory dishwashing liquid, now its ready to use.

To use, add 1 to 1 1/2 cups per 2 gallons of water, and spray to clean off dust, help get rid of fungus gnats and other bugs. To use for watering plants use 1/2 cup of soap to 2 gallons of water. This can be used both indoors and out in the garden on everything. I use it on my Heirloom Tomatoes and I don't ever see bug damage!

To really control bugs I do the following:

This is what I do, firstly use softsoap water to control the gnats, using sticky traps work very well. But what I found really works best is to nuke the soil in a thick plastic bag that won't melt in the microwave for 10 minutes or so. What you want to do is to get it to boil and kill off everything! Once the soil cools down to room tempature, you can now replant the plants. When I get or buy a plant, I keep it away from the rest till I know its bug free, I spray it with softsoap water and then remove the soil that came with it and throw it away, then I use my own mix. This has been the only way,(For Me)I've found to keep the fungus gnats and other bugs from taking over.
Hope this helps, farmerted361:)

I would agree with tapla, 1:128 is too much but I would not hesitate to add a quarter to a half teaspoonful to a gallon of water. I don't know any reason to do it unless you are attempting to correct some situation such as quick wet down some unusually dry soil, or as someone else above suggested, to wash off leaves.

You know that plant in the back that you missed a few times (ahem) and now it's bone dry and wilted and the water just runs right through? Add a few drops of dish soap to a bucket of water and drop the plant in, pot and all; the surfacent helps the water absorb into the soil.

I don't see why you'd need to add it on a regular basis.

Korina

'Butter wouldn't melt in my mouth. Well, it would, of course it would, but *very slowly*.' ~Wolf

Korina, I think I'll take your advice. WIsh I had learned this sooner! The book was written 20 years ago, and maybe soil mixes have come a ways since then. I won't be adding liquid soap on a regular basis, but for the situation you describe, I think it would be a good thing. Thanks!

I'm glad that there is a post about this!! I had a problem with an arcea (sp?) palm I got having fungus gnats and something spotty on the stems. I've been spraying it daily with a mild dish detergent/water mix and successfully got rid of the gnats and the spotty stems, but I was worried about the dish soap getting into the soil, but hey, I guess it's good for it! Thanks everyone! :)

I sometimes add a couple drops of dishsoap per gallon of water..but I do so more as a foliar spray. It's a great bug repellent, and if there are bugs such as mites, the soap will help rid them..Toni

I work at a greenhouse and we mix our own soil, mixing all the components; black dirt, peat moss, perlite, time release fertalizer, and a wetting agent that is essentially powdered soap. It helps with water absorbtion and helps keep the soil from crusting over as much. I guess I would feel alright about mixing soap into my water but like many have said you probably wouldn't need a whole lot.

If you just want to get your soil saturated you can simply put the container in the sink or tub and let the soil absorb all the water it can, this is also good if you are using clay pots because the clay is so porous that it will steal the water from your plant, so soaking them also allows for the container to get "watered". I usually soak the containers for different times based on container size.

hope that helped, sorry I went on so long.

I don't routinely use it but I have on occassion had potted plants dry out so bad the mix shrinks away from the side of the pot and water runs right off. A couple tiny drops of dishwashing liquid on the surface will allow the water to soak in and rehydrate the root ball.

Hello, um I'm writing report for my biology classes from experiment in which I watered plants with mixture of soap and water and I need some quotation to proof my results. The book eileen_plants mentioned seems suitable, but it is not available in my country, so I want to ask if someone could write here the quotation about watering plants with soap? It would be so much help for me

Okay, sechmet0728 I'm 60 years old and I cannot scientifically say that regular watering with soap is better than just rarely doing it. However, When I was a child "Physically not mentally as I am now" We ran our washing machine into the backyard of our farm. We found and everything that grew up on a farm gew better around the discarded washing machine and I will tell you plants grow three times or more rapidly than plants that are watered with just water.

In addition, I never ever seen a problem with the soil hardening as I have read several internet "experts say": That soapy water hardens the soil and it's only good for insecticide use. Well if you don't water your soil of course it will get hard unless it's dang good soil. We had clay a day without watering would turn the ground into concrete. Since we washed clothes everyday ( we were poor and I only got three pair of levi's and four shirts at the start of the school year. That's all I had so washing everyday was essential.

An experiment you can do for class is simple. Take two Tomato plants. Place them in separate pots. Water one with very diluted soapy water. Or take your dishwater water out of your sink if you wash dishes by hand. Keep a diary and pictures on both plants. Plant A has soapy water, Plant B has just water. Do not fertilize either of them at all; just water for B and soapy water for A. You will find that the A plant will do exceptionally well as the B plant will grow; but not even half as well. This is true and it will work. No matter what you read on the internet. I use Grey water to water my fruit trees and my lower garden I have water even in times of drought. This is just one of many to use less water.

So this is my proof, hope it helps

David The Tinkerer Gajetest.com

Since sechmet asked that question in September of 2014, I'm sure he completed it a while ago.

Let's see. Joe Bob got scratched by a cat on Tuesday. By Thursday Joe Bob had a raging fever. Joe Bob Died on Friday. No question about it - Joe Bob died of cat scratch fever - that about right?

Detergents are HARMFUL to plants. You might not be able to tell, but I made the period after that sentence bold. It's possible that the gray water dumped on the lawn A) Didn't contain a detergent, but instead contained a soap B) The soap might have been made from potassium fatty acids and probably a good measure of phosphates, which if the soil in the area was deficient of P or K would account for better growth even if at the same time roots were being damaged C) If a P or K deficiency was the most limiting factor, you would expect vitality to improve, but only within the limiting impact the soap or detergent had on root health/function. IOW, there are several plausible explanations or alternate courses that might have been utilized to stimulate even better growth/health w/o risking root health/function. The logical fallacy committed in my example and the premise that dishsoap/gray water should be considered as a part of someone's nutritional supplementation program is called 'confusing cause and effect' or 'questionable cause'.

Most horticultural myths arise from people making up science to fit what they think they are seeing and then treating it as fact. I sure hope people don't start watering with dishwater as the outcome isn't likely to be desirable.

Al

I know nothing about this subject, and don't plan on using detergent in the water that I use on my plants, but for those who do, I wonder if there is a better alternative. When I do laundry, I always like to use a little bit of Calgon Water Softener. It's not a fabric softener, it's a water softener. It makes hard water softer. I find that the water lathers up more, and my clothes come out cleaner. Might this product be used instead of detergent, if any surfactant is to be used at all ?

Manuel

Try alfalfa sprout juice as a surfactant. There is a good chance that it is good for your plants.

Put alfalfa sprouts in a blender with a small amount of water, blend, wait for the foam to settle, and strain through a paper towel.

...... and the fungus gnats will show their deep appreciation.

HKG - since the main bulk of Calgon Water Softener consists of sodium citrate, sodium polyacrylate, and sodium sulfate, it's a pretty sure bet it would be highly phytotoxic even if only because of its Na content.

Al

"David Adkins

Okay, sechmet0728
I'm 60 years old and I cannot scientifically say that regular watering
with soap is better than just rarely doing it. However, When I was a
child "Physically not mentally as I am now" We ran our washing machine
into the backyard of our farm. We found and everything that grew up on a
farm gew better around the discarded washing machine and I will tell
you plants grow three times or more rapidly than plants that are watered
with just water."

When I was a kid we did similar things and saw similar results. The positive results may have been due to phosphates in the waste water which are now discouraged for environmental reasons. Potassium in homemade soap would have some positive affects too if the soil has enough buffer capacity** to handle the pH.

** I get the feeling that buffer capacity is not taught in high school science these days. It is tedious and complex. Perhaps gardeners find it easier to forget.

"...... and the fungus gnats will show their deep appreciation."

How dare you call these forum members, "fungus gnats"?

Jus sayin ...... whizzing up an organic punch and applying it to indoor plants is like sending out a dinner invitation to every fungus gnat in the neighborhood.

Al

Ding Ding

"Jus sayin ...... whizzing up an organic punch and applying it to indoor plants is like sending out a dinner invitation to every fungus gnat in the neighborhood."

You are implying that there are fungus gnats in the neighborhood. Assuming there are fungus gnats, there are easy countermeasures, including throwing some tobacco into the blender with the alfalfa sprouts. And, this is still an "organic punch."

The marijuana community uses Wet Betty:

http://www.ebay.com/itm/Wet-Betty-Organic-/261607228770?hash=item3ce9018562:g:-kEAAOSwxH1UJeix

(the picture on that label makes me laugh)

and you can buy the active ingredient in Wet Betty much cheaper here:

http://www.ebay.com/itm/Yucca-Extract-Yucca-Schidigera-Saponin-Powder-Wet-Betty-WETTING-AGENT-SM-90-/161289126445?var=&hash=item258d94c22d:m:mjVtqzMEvbHvnMLubvguNew

If the marijuana community uses it, it must be invaluable ..... and I think it's safer to assume/imply there ARE fungus gnats in the neighborhood than imagine there are not.

That's all wonderful if you need a wetting agent and don't mind the smell of rotting alfalfa and tobacco, but it seems like a lot to go through when the grower has absolutely no idea whether or not what might be in the alfalfa/tobacco juice is actually needed by the plant. When a fertilizer supplementation program is on point, adding 'this and that' in the hope it will be to the plant's advantage is far more apt to end up being a duplication of nutrients already in the soil solution in appropriate amounts and therefore to the plant's disadvantage. An excess of any nutrient has the same potential to limit as a deficiency.

Al

"If the marijuana community uses it, it must be invaluable"

Since it is the number one cash crop, I listen.

"..... and I think it's safer to assume/imply there ARE fungus gnats in the neighborhood than imagine there are not."

I haven't seen a fungus gnat in a long time.

"That's all wonderful if you need a wetting agent and don't mind the smell of rotting alfalfa and tobacco"

You have a despicable habit of making up hypotheticals and then pretending that they are real. You don't anything about the smell of rotting alfalfa and tobacco because you never tried it. Besides, many houseplants are outdoors right now where it doesn't matter. Incidentally, did you stop beating your wife?

", but it seems like a lot to go through when the grower has absolutely no idea whether or not what might be in the alfalfa/tobacco juice is actually needed by the plant."

No, it is less work to perform a controlled experiment than it is to decipher your excessively verbose BS.

I came to this subject for the following reason. I have serious mole problems in my garden. Commercial mole repellent is expensive, takes a lot of water and is less that totally effective (maybe nothing is). But a web recipe for making my own includes equal parts dish soap and castor oil, added at the rate of 3 TBS per gal of water. In desperation I tried it on the biggest mole invasion sites and it seems to be considerably more effective than anything else I've tried (many, many things). So what I want to know is what's it doing to the plants? Are they still organic? Anyone have any idea how long it might deter the critters, so I can figure if it will need re-doing? Thanks!

Yessssssss

I know very little about growing plants, but I have veral types and have been bitten by the african violet bug. I've used a pretty strong concentration of dawn and water to soak self-watering wicks for starting AVs from leaves. They don't seem to mind the Dawn at all

Please avoid using home concoctions as an insecticide. IOW, please do not apply home concoctions to the plant topically or as a soil drench. You will be far more likely to have created a toxic brew harmful to plants than a mixture effective at reducing insect herbivory. It should still be made clear that whipping something up at home and applying it to plants because it's capable of killing insects is not a good idea.

Al

This is the 2nd place I've seen this post today. Please stop spamming the internet with this.