Author Topic: soil wetting agents  (Read 1318 times)

brian

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soil wetting agents
« on: March 15, 2023, 03:23:08 PM »
We all spend a lot of time thinking about soil mixes and drainage.  I have personally seen severe tree damage or death caused by large dry areas of hydrophobic soil inside of a container mostly caused by too much peat moss.  But whenever I buy some decorative plant or use seed starting soil I am always amazed to see mostly-peat soil draining like sand.  I now know this is because they have added wetting agents.  It makes me wonder... why not just add wetting agents to all container plants with ever repotting (they don't last forever).  If I search for 'wetting agents' I get a mix of:

 1) scientific articles not specific to agriculture talking about wetting agents in a general chemistry sense
 2) various soil wetting agents for sale
 3) instructions on how to make your own wetting agents, seeming to always be detergent soap + water

So, we all know plants don't like salty soil, so dumping soap into the soil doesn't sound like a good idea at all to me.  Of the many wetting agents for sale, I can't really understand the pros and cons of different types.  Anybody have experience with this?

Is there a low cost wetting agent that I can safely apply to my container trees?

brian

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Re: soil wetting agents
« Reply #1 on: March 15, 2023, 04:06:25 PM »
I interrogated ChatGPT about this and it seems that most common wetting agents are plain soap and polysorbate, both of which I already have.  And wetting agents and surfactants (used for insect-smothering and foliar fertilization spays) are much the same thing and used interchangeably.  The soap I use for smothering insects is "Dr Bronners pure castile soap" which is a salt of potassium (not sodium) so it shouldn't cause salinity issues in soil.  I can't find a satisfactory answer on how long these remain effective in soil... seeing anything from days to months.  If it must be included in every watering it is a dead end for me as I have too many plants to amend every watering. 

Seems there are some granular agents that might last longer, looking into that...

tru

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Re: soil wetting agents
« Reply #2 on: March 15, 2023, 07:11:04 PM »
Yucca! but you have to add it to the water I think not the soil so I'm not sure if that would work
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brian

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Re: soil wetting agents
« Reply #3 on: March 15, 2023, 07:14:49 PM »
Yucca! but you have to add it to the water I think not the soil so I'm not sure if that would work

I found this recommended various places... when digging a bit it seems to be yucca "saponins" aka soap, right?  Much of what I am finding is basically "use soap" but ideally non-detergent potassium-fat soap.  And it looks like the liquid types are close to every watering. 

caladri

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Re: soil wetting agents
« Reply #4 on: March 15, 2023, 07:31:03 PM »
Saponins are not the same as saponified fats, which are salted in the way you're mentioning desiring to avoid. Saponins are not salted fatty acids.

1rainman

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Re: soil wetting agents
« Reply #5 on: March 15, 2023, 08:38:00 PM »
I buy potting soil with wetting agents added and plants do poorly in them and they don't seem to work as far as holding water so I avoid them. Peat holds water really well but will also dry out quickly on hot days. Peat doesn't have much drainage once waterlogged it needs sand or perlite to keep from being too water logged. Which normal soil is peat and perlite.

I just add clay in the form of cheap cat litter. It works really well and is cheap. The main problem I have is less soil and more container size. Small containers get waterlogged easily and dry out easily. Watering them is a science. When I put them in giant containers with my soil mix I don't have to worry.

I add a tiny amount of sand but everything dries out quickly in this heat. Being waterlogged only seems an issue in small pots. I add a small amount of clay and mulch it makes a huge difference in keeping it from drying out.

brian

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Re: soil wetting agents
« Reply #6 on: March 16, 2023, 11:41:46 AM »
To be clear, I am not looking for a wetting agent to retain water, but one to cause water to flow more freely through the container to avoid hidden dry pockets. 

I know that soil mix is the best way to handle this, but I'm thinking of wetting agents as an additional safeguard. 

poncirsguy

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Re: soil wetting agents
« Reply #7 on: March 16, 2023, 12:53:28 PM »
Best wetting agent is warm water with the root ball completely submerged for an hour or more.


Titanic took 2.5 hours to be fully wetted
« Last Edit: March 16, 2023, 01:14:03 PM by poncirsguy »

Millet

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Re: soil wetting agents
« Reply #8 on: March 16, 2023, 01:03:22 PM »
I tend to go with poncirusguy.  To avoid dry pockets, simply soak the problem container in a larger container for 1/2 hour more or less every  month or so.   Works every time.

brian

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Re: soil wetting agents
« Reply #9 on: March 16, 2023, 01:49:08 PM »
You are absolutely right that soaking the containers in a tub of water solves the problem, but I have a *lot* of containers, it would take all day to do them one at a time :)

Seanny

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Re: soil wetting agents
« Reply #10 on: March 16, 2023, 04:03:48 PM »
I add plaster sand to the top.
It slow down water draining.

poncirsguy

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Re: soil wetting agents
« Reply #11 on: March 16, 2023, 05:21:29 PM »
I have 9 trees up to 15 gallons.  Put 1 in the soaker with feed and go off to other chores.  2 hours later switch trees and more chores.  switch out and fx& eat lunch.  etc.  it takes very little labor time to soak all 9 trees

1rainman

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Re: soil wetting agents
« Reply #12 on: March 16, 2023, 06:59:33 PM »
Once peat is wet it stays wet. I just soak it several times when new. Never knew dry spots were a problem.

Galatians522

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Re: soil wetting agents
« Reply #13 on: March 16, 2023, 10:26:45 PM »
If you want to do a thorough soak, a thick plastic trash bag could be slipped around the pot, filled with water, and tied to the trunk. A pot saucer is another option that might work.

pagnr

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Re: soil wetting agents
« Reply #14 on: March 17, 2023, 02:47:02 AM »
Horticultural wetting agents when applied at correct rates should wet up pot mix, and as a surfactant, increase drainage
Something similar to a clean windscreen or kitchen sink. The water flows away after soap is applied.
Too much wetting agent can cause big problems with excess water holding.


Millet

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Re: soil wetting agents
« Reply #15 on: March 17, 2023, 12:15:10 PM »
rainman I cannot agree with your statement. "once peat is wet it stays wet".. As time goes by of course it DRYS out, and that is why one has to water again.
« Last Edit: March 17, 2023, 12:19:26 PM by Millet »

Walt

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Re: soil wetting agents
« Reply #16 on: March 17, 2023, 12:22:13 PM »
I do what Millet and Poncirisguy said.  If I need to mow or do garden work I do that while a pot is soaking.  Or reading a good book works too.

1rainman

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Re: soil wetting agents
« Reply #17 on: March 17, 2023, 06:34:51 PM »
But the whole thing is wet or the whole thing dry. But I soak stuff when watering.

Millet

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Re: soil wetting agents
« Reply #18 on: March 17, 2023, 09:40:53 PM »
rainman, I see what you meant, and you are correct in that matter..  Over time water develops drainage paths, then some spots in the container become hard dry. These spots and are very difficult to rewet.  Therefore, he container must be soaked to rewet them.

Lyn38

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Re: soil wetting agents
« Reply #19 on: March 31, 2023, 11:42:25 PM »

Is there a low cost wetting agent that I can safely apply to my container trees?

Yucca isn't low cost, but it doesn't need to be added all the time. Just every once in a while as long as your not leaching the soil out. It can easily be leached out of the soil as it's not so sticky as soap. Give it a really good soak in a large pail or tub or something the first time around. Humic acid can be very cheap by the gallon if you shop around. It has a tendency to help soil moisture a little bit and is good watered in once in a while. You could also occasionally put a small amount of molasses in the water. Ants hate molasses, which is a plus. Plants like it- extra carbs.

Oolie

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Re: soil wetting agents
« Reply #20 on: April 01, 2023, 01:40:22 PM »
I find molasses works great, but it only takes a little.

pagnr

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Re: soil wetting agents
« Reply #21 on: April 01, 2023, 03:55:03 PM »
Coffee grounds seem to have a wetting quality.
More so the water from strained used coffee grounds.
Don't overdo it with the actual coffee grounds on the surface of pots.
They can cause a boost in microbes, leading to clumping and surface matting, the opposite of the wetting you wanted.