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charles_hudak

Hydrophobic soil

chudak
12 years ago

I'm having the strangest problem in my whole garden...

I had horrible luck with everything this year. I have two 4x4 raised beds and two large in ground beds. Peppers, herbs, tomatos, all seemed rather stunted. I watered frequently but many seemed to be dying. At first, I thought it was because I was watering too much. Then I did some digging, literally.

After watering my beds well, I dug into the soil with my hand. To my surprise, the soil an inch below the surface on down was BONE DRY. It seems that the soil has a very high surface tension and it literally shrugs off the water. I've tried hoeing it up to mix it to no avail. No matter how much I water, the water mostly just puddles and runs off, it won't soak in. When I mix in the handfuls of soil with water, you can see the soil floating on top of the water like a sheen of powder.

It's the strangest darn thing I've ever seen and needless to say I'm flummoxed. I need to solve this problem by next spring or I might as well give up gardening--none of my plants are getting more than a token amount of water no matter how much I water.

The only 'common' attribute amongst both my raised beds and my in ground beds is that I mulched in a bunch of the municipal compost available at our landfill. It seems that there is alot of very fine powder in the compost and that powder is very hydrophobic.

Is there any soil amendment I can add to fix this or am I faced with scraping 4-6" of top soil out of my in ground beds? My raised beds are a total loss. Even after making a big mud bog out of them and mixing the soil with water, the next time I try to water, the soil still won't soak in.

Appreciate any suggestions.

Charles

Comments (35)

  • kqcrna
    12 years ago

    Soap. Spray the soil with soapy water to act as a wetting agent and lower surface tension, then water the soil. Best method would probably be a long, slow drip with a soaker hose. See if that helps as a quick fix.

    In the long run, adding more organic matter should be your goal. The municipal compost doesn't seem to have worked too well, (don't you wonder what's in in???) , might want to consider other sources.

    Have you had this problem in past years? Had a recent drought?

    Karen

  • Kimmsr
    12 years ago

    Many soils, if allowed to get too dry before applying water, will exhibit hydrophobic attributes. A garden soil should never be allowed to get that dry since plants cannot uptake needed soil nutrients from dry soil, and that is why it is necessary to keep the soil of a garden well mulched. If your soil was "bone dry" and inch down you simply did not provide the garden enough water, often enough, and the soil is not mulched well enough.

  • Lloyd
    12 years ago

    Well Charles, I guess you've been told!

    If this is the first time you've had this issue arise and it coincided with the usage of the municipal compost, I suspect I wouldn't use that stuff anymore.

    But here is what I would do if I were in your shoes. I'd go find (buy if I had to) some really high quality compost, not a lot, just a bag or two. Mix about an inch or two of this good stuff into the top 3-6 inches of your existing soil in a small area of one of your problem gardens and see how that impacts your dilemma. It might not do any good but the cost is small and the work involved is minuscule. If it helps, I'd go that route for the rest of the garden myself.

    I'd also consider using some "not quite mature" compost in another small area to see if the infusion of those micro organisms helped alleviate your problem. This might take a bit more time to allow the immature compost time to do something in the existing soil.

    What about watering with a compost tea? Never used the stuff myself but it might be worth a small experiment as well.

    Good luck

    Lloyd

    Disclaimer: I'm not a gardener and I could be full of crap.

  • socalgal_gw Zone USDA 10b Sunset 24
    12 years ago

    It might be how you're applying the water. If I have very dry soil and water with a hose, or even a drip hose, I have a similar problem. If Mother Nature waters with rain, the water goes in much further. I think the slow, steady sprinkling works better.

  • jeroldrburrow
    12 years ago

    Hi chudak -

    I agree with kimmsr. I'm in San Diego as well and applied compost from the Miramar Landfill to my garden last year. Everything grew great and I didn't have any soil wetting issues.

    Also, I found that mulching with straw worked really well for me. Definitely a necessity during the summer months here in San Diego.

    --
    Jerold Burrow

  • rj_hythloday
    12 years ago

    Get your self lots of OPBL and other OM and mulch or compost it. Nothing like lots of OM to fix everything wrong w/ soil.

  • jeroldrburrow
    12 years ago

    Well, it only makes sense that municipal compost's contents fluctuate quite a bit. Maybe I got a 'good' batch last year?

    On a related subject, have you heard of this place:

    CCD Mushroom Farm

    According to their web site you can pick up mushroom compost for free if you are able to haul it away yourself. I've tried e-mailing but it bounced back. Might be worth a look. I plan to drive up there one of these days to check it out.

    --
    Jerold Burrow

  • idaho_gardener
    12 years ago

    I think Karen is right on. I'd try using baby shampoo. Also, you should get your soil tested to find out its fertility characteristics. NPK and pH.

    I'd also look for bags of humic acid and start applying that to the garden to condition the soil. Keep it mulched even if you have to use cardboard. San Diego is hot, dry, and windy, so protect the soil.

    Next year, I will try mulching my vegetable beds with partially composted OM. My strawberry beds loved getting grass clippings, and the raspberries loved the spruce needles as mulch.

  • Kimmsr
    12 years ago

    You could add some kind of soap, baby shampoo is a detergent that might work but could add unwanted stuff to your garden even in the small quantity you would use, which will reduce the surface tension of the water and allow it to flow somewhat easier but that is not going to correct the problem, hydrophobic soil. Adding organic matter will do that.

  • reg_pnw7
    12 years ago

    Sandy soil is not normally hydrophobic. Dried out organic matter can be. Clay definitely is, I've had tons of experience trying to keep heavy adobe clay soil watered in NorCal ... you have to apply the water very very very VERY slowly. Like trickling overnight for a tree. I'd use 1/2 gallon/hr emitters on smaller plants like veggie gardens. And let it run for hours. Sometimes I'd break up a watering session over a couple of days to give the water time to soak in.

    Sandy soil is the opposite - that's what I have here in WA, and the water runs right through it. Now when it's been left to totally dry out over summer, the first rains do tend to not soak in very well at first, but nothing like clay. For instance, this fall was very dry at first. The soil was bone dry all through September with no rain. Then the first week of October it rained 3 inches. I dug up my garden after that. Some spots were damp down about 2". Others were still bone dry below the surface dampness. Nothing was wet past 2". And that's a sandy soil after 3" of rain!

    I'd go with the surfactant, like soap, as has been suggested; then I'd water a LOT slower a LOT longer. If it's both in the ground and in raised beds that you're having the problem then it's not just the native soil's texture that's the problem - probably watering techniques.

    Here's what WSU Extension has to say about watering sandy soils: One inch of water penetrates into 12 inches of sandy soil, compared to 4 inches in clay. Sandy soils will accept anywhere from 1/2 to 3 inches of water per hour, compared to 1/10 to 3/5 inch per hour for clay. A direct quote: "A very dry clay loam soil could take as long as 120 hours to completely wet to a depth of 12 inches. A sandy loam, however, might take as little as 4 hours." (Drought Advisory EB 1090, Watering Home Gardens and Landscape Plants, WSU Extension, available from http://pubs.wsu.edu)

    4 hours at an inch per hour is probably longer than you've been letting the water run. 1" of water = approximately 1/2 gallon per square foot of garden. You can do the math to see what it will take to get that top 12" of soil thoroughly wet. Once wet you just need to top it off as water is used up by the plants. Raised beds drain faster than the ground does, and you probably used imported soil so the texture is different too, so don't assume that the same watering regime will work for both.

    It could be the compost, but I'd examine your watering practices first.

  • luckygal
    12 years ago

    Hope everyone who decides to use a surfactant knows the difference between soap and detergent. Soap could be organic but detergent certainly isn't.

    I'd be inclined to agree with the poster who recommends examining your watering practices. If soil "shrugs off water" where is the water going if you are watering sufficiently?

    I would mix that top 4-6" of "topsoil" you have with what's underneath then add something really good like a quality compost you can make yourself in your warm zone. I like making my own compost and mulch cause I know what's in it.

  • Kimmsr
    12 years ago

    I find my sandy soil to be very hydrophobic. It takes a lot of water to get really dry soil to start taking that water in instead of having that water run off. The same thing will happen to the beach sand, if you put some water on that sand it will simply puddle and not soak in for quite some time. The same thing can happen to any soil well amended with organic matter, if that soil is allowed to get too dry before more water is applied.

  • joe.jr317
    12 years ago

    I don't know the soil properties of San Diego, but in Indiana the clay can be a little tough to get wet when let go too long. It just takes longer. The only way to correct that permanently, as opposed to the soapy quick fix, is with organic material as others have said. You did that. Now you just have to get it wet. Mist it all. Then cultivate it just a bit. Mist again. Cultivate. Then water deeper. I place a shower wand directly to the ground. Sometimes, it doesn't hurt to poke an inch wide hole here and there with a sawed off piece of PVC. Saw a sharp angle to press into the ground. If it's hard to press in, that is your biggest problem. You have too much compaction. If it goes in easy, then take a plug and then water will penetrate. As long as you stay on it, you will be able to get your soil back to right in no time. Check the pH of the soil, too. Also keep in mind that it takes a lot of water to penetrate deeply. One of the most common mistakes people make is thinking they have watered deeply because the top inch appears soaked but the next several inches are untouched. People sometimes just don't realize how much water it really can take.

    Was the compost bone dry when you got it? If not, then the compost wasn't the problem. Frankly, it couldn't have always been bone dry even if it was when you picked it up or it would never have become compost.

  • plus2
    12 years ago

    Add 1/2 pound/per acre of white granulated sugar to your beds. Also add some calcium at the same time. The sugar will add a good quick carbon source and the calcium will act as a stabilizer to the nutrients that will become available through the biological activity that is stimulated by the sugar. The sugar can either be dissolved and sprayed via warm water and a sprayer or placed right on the bed. I would suggest spraying for better coverage.

  • kqcrna
    12 years ago

    I still think the best way to soak, and get it deep, is to use a very slow drip on a soaker hose. I might let it run in one spot like that for 8 hours. Has to be a very, very slow drip, as in hard to even see that it's dripping. It will soak very deep down into the soil, and then it takes a long time before it dries out.

    I did that to some of my worst, driest areas during our drought last summer and it worked exteremely well.

    Karen

  • Lloyd
    12 years ago

    "It seems that there is alot of very fine powder in the compost and that powder is very hydrophobic."

    and

    "When I mix in the handfuls of soil with water, you can see the soil floating on top of the water like a sheen of powder."

    These still cause me to be concerned. When I read it the first time, an image of ground up pallets popped into my mind. I remember reading stories of municipal composts being made with this material just to get rid of it and as a cheap and widely available carbon. I'm just speculating, but if the OP had successfully raised a garden previously and now he is having trouble, something has changed.

    Lloyd

  • pkapeckopickldpepprz
    12 years ago

    I noticed this same conundrum with the Florida Sugar Sand and ironically water puddles on it instead of being very well draining like people always assume about sand. What can be done to improve this as I want to start taking better care of a Bermuda lawn but runoff is a problem and I'm not made of $$$$ to just have the hose running 24/7. Heck I remember after one of the tropical storms or hurricanes last year we got a bunch of rain but digg down a few inches and it is bone dry. What is this crappy sugar sand and what can be done to improve it?

  • 11otis
    12 years ago

    Hi chudak,
    I have to tread lightly here because I don't know you guys (yet) and you measure your gardens with acres as I do it with sq.ft. Sometimes not even that, I measure with 1gal pots, 2, 3 or 4 gal.

    Anyway, you mentioned 2 beds of 4x4 and I think that is managable to my proportion. Have you ever tried coco-coir? When it is left bone dry, unlike peat moss, coco-coir will readily soak up water up to 8x its volume. Unlike peat moss which tend to be acidic, cc-coir is neutral. It will not break down so easily like peat moss does. However, it does not have any nutritional values. I have been using it to mix with my soil for water retention and soil "filler". I am buying the 5kg (11#) blocks and pay about $10 CDN.

    Do you think that will help you fix your beds?
    Otis

  • chudak
    Original Author
    12 years ago

    Just to follow up this post...

    After some nice winter rains here in So Cal I can state that my soil has finally wetted completely. A few earlier storms that only dumped a half inch or so didn't do the trick (surface soil wet but dig down and still dry) but the last couple that pelted us with 2-3 inches did.

    I guess I'll pay more attention from here on out and keep the soil well mulched and water often enough to keep the soil from drying out below the surface. My previously stunted italian parsley in my raised bed is now a bush about a half meter in diameter and over a foot tall.

  • kqcrna
    12 years ago

    chudak: I'm glad to hear that Mother Nature is helping you. It's always amazing how a few good rains can saturate everything, but human attempts for weeks or months can show so little improvement. You really will have to maintain your watering plan to prevent the same things from happening again.

    As a side note, my good friend is a homebuilder and has been for 30 years or more. He has been astounded in recent years at how our soil has gotten progressively drier for about the last decade. While we had our hottest/driest summer ever in 2007, but a relatively wet 2008, he said that when he's digging down 8 feet or so to pour foundations the soil is completely dry. It's been such a slow and steady decline in soil moisture depth. I had no idea what goes on under the top foot or two of earth, the limit of how far down we'd normally dig.

    Moral of the story I guess is that most of us only know the condition of the relative surface of our properties and we shouldn't assume that things are OK down there.

    Karen

  • pkapeckopickldpepprz
    12 years ago

    Does anyone know or can address the specific issues with the hydrophobic nature of sugar sand? Kind of an oxymoron really..

  • marshallz10
    12 years ago

    Well, I've experienced sugar sands in New Jersey; wet or dry this very fine silty material is unstable, will not bind up. The material will be hydrophobic, resisting the passage of water through the soil column. The particles are mostly silt-sized but typically there is some coarser sand-size particles and even fines of organic materials mixed in. Little or no clay to help bind or to absorb moisture in its platy structure. Clay also assist in aggregating the soil particles into larger peds and so allowing better flow or water and gases in the soil.

    In California there are mesas of shallow marine sediments and old beach deposits, including sugar sand lenses. We are talking millions of years old stuff and acts just like the sugar sand in NJ. Personally I had silt soils; I'd rather garden or farm in sandier or more clayey soils. Silt soils don't really hold much nutrients.

  • pkapeckopickldpepprz
    12 years ago

    Marshallz, so you are saying what is called sugar sand is actually silt? I wonder why quicksand isn't called quicksilt?

  • marshallz10
    12 years ago

    Not all silt is created equal. Wind (aeolian) silt includes deposits called loess that serves as some of the richest and deepest soils in the world. Sugar sand silt is different, of marine origin I think and so has grains well rounded rather than angular and rough. That is my understanding. I'm too lazy to google!

    Some quick sand is comprised of substantial sand. What usually makes quicksand work is a spring or subsurface flow keeping the material in partial suspension.

  • boogerblaster
    8 years ago

    I'm going out on a limb, but this sounds like a chemistry problem. Try adding gypsum (calcium, essentially) to the soil, and applying plenty of water to try to leach away any salts that might be causing the soil to act that way (the calcium interacts with the soil particles to displace bound-up salts, which are then able to be absorbed into the water and are leached away).

    I'm not an expert, but I did take two semesters of soil science in college a long time ago. If I remember correctly sulfur can be added to achieve the same effect at a cheaper price, but it only works if calcium carbonate is already present in the soil. It also lowers soil pH, which may be a good or bad thing depending on your situation.

    If you happen to have any old, decaying wallboard lying around, you can smash it into pieces, remove the paper, and add that to the soil as well. The white guts are made out of very pure gypsum.

  • nil13
    8 years ago

    booger, odds are the OP, being in Southern California has plenty of Ca in the soil already.

  • Garden.Geek
    8 years ago

    Half gallon milk jugs. :) Drill some holes in the bottom and lower half and bury them between the plants. Fill each up with water and it will soak through the holes into the deeper soil. While you certainly want to amend the soil for water retention in the long run, this may help until then, especially when the temps soar. I don't have a problem with water absorption, but this method has proven to be a great help in the middle of the summer when the air here basically sucks the moisture out if the soil by mid-afternoon. :D

  • ernie85017, zn 9, phx
    8 years ago

    So glad to find this post! I realized that I have the same problem in my front raised beds.
    Today I cultivated, and watered with a cocktail including bronner's soap.
    How strong can you make the soap? I used a siphon in a 5 gal bucket, and 1/2 oz soap in the 5 gal bucket. I am wondering if this was just too weak?
    How many times should this be repeated? Am I treating the water or the soil?
    Let's hear it for Gardeweb!

  • klynn24
    8 years ago

    I'm with Ernie, so glad I found this post! I've been gardening for years and always frustrated when after watering to find only the top few inches wet. Explained this to other gardeners, landscapers, etc. only to see perplexed looks. FINALLY, realized the soil needs to be watered slowly (using a soaker hose works well). Also, since clay particles are small (smaller than sand particles) and pack easily, it's helpful to add a coarse amendment. This opens up the soil so water can penetrate. I've used Kellogg's Garden Soil and/or Omni. Pumice is also helpful.

  • cowchip
    8 years ago

    I live at the base of a mesa (actually ancient sand dunes) near Pismo Beach. It is basically dirty, powder-fine sand that retains zero water. Ammending with OM is good for nutrients, but there is no clay component to the soil acting as a binding agent. Water simply disappears.
    Is there a clay type ammendment that will bind sand and OM together? It occurred that I might sparingly use plain, unscented, clumping cat litter to create a clay component. If thoroughly mixed in, might it eventually distribute itself evenly and hold water better?

    Anyone with experience in this area?

  • cowchip
    8 years ago

    I live at the base of a mesa (actually ancient sand dunes) near Pismo Beach. It is basically dirty, powder-fine sand that retains zero water. Ammending with OM is good for nutrients, but there is no clay component to the soil acting as a binding agent. Water simply disappears.
    Is there a clay type ammendment that will bind sand and OM together? It occurred that I might sparingly use plain, unscented, clumping cat litter to create a clay component. If thoroughly mixed in, might it eventually distribute itself evenly and hold water better?

    Anyone with experience in this area?

  • pmychang
    last year

    What is OM?

  • gardengal48 (PNW Z8/9)
    last year

    Organic Matter

  • toxcrusadr
    last year

    Not much talk about mulching in this thread. A good spongy mulch would absorb water and let it soak in slowly, as well as keep the ground surface moist so it can't dry out and become hydrophobic again.