Too much of a good thing

Just got my fall soil sample test results back from Clemson. I have "Excessive" levels of Phosphorous and Calcium in all my beds, plus the veggie garden. Clemson is really good at telling you how to correct defficiencies, but somewhat sparse on how to correct "Excess". The Master Gardener I talked to suggested it was due to my practice of covering everythingfor the past 20 years with organic mulch(mushroom compost, stable scrapings, lawn clippings, etc.)for weed prevention in spring and fall plantings, then tilling the mulch in at end of season,. replanting, remulching it for the next crop/season. Suggested I stop my practice of using organic mulch for awhile, and retest in the spring. I always thought if you stayed with organics, you couldn't get an imbalance like I've got. Any insight on this? Any way to drop the phosphorous/calcium in my soil? I'm loathe to give up mulching with organic stuff because I can't keep ahead of the weeds without mulch (no one could!)...

I'm no master gardener (lol), but there's no reason to steer away from organics altogether, however, it might help to adapt things for a little while. Did they give you a ph level when your soil was tested? from what I read it sounds like both calcium and phosphorus are affected when the soil is on the alkaline end. If that is the case, you could swap out pine straw , sawdust, or other slightly acid mulch for the grass clippings, and let the stable scrapings compost next year. I was glad to see this thread because I hadn't thought that grass clippings contained much phosphorus, until I read up. Adding potassium (wood ash,kelp meal, comfrey leaves, etc, there are threads on this in organic gardening) might help your plants take in the phosphorus better also. I don't honestly see how mushroom compost could do any damage, though. If you grow a lot of tropicals or other heavy feeders they will probably be fine with the excess, they might love it!
Here's a good article I found on calcium
http://www.spectrumanalytic.com/support/library/ff/Ca_Basics.htm

an an ok one on phosphorus
http://pss.uvm.edu/ppp/articles/phos.html

Hmmmm , I am a Master Gardener and the first question I would ask is if this is a new problem? How have the soil tests been in the past? If it is new them maybe you do need to review your cultural practices although I have never heard of too much compost causing issues. I wonder if whoever you spoke with did not take your location into consideration. The Stono is probably a lot like the Morgan where I live and there was a good reason phosphorus was mined along the banks of these rivers - it was and still is plentiful here. But, this should have showed up in previous tests if you had them.

I have been told the reason my soil is high in calcium is because it is made up, over millions of years, from shells that have been broken down into sandy loam (or muck in my place.) That sounds plausible to me.

Methinks the high powered computers that test our soil do not take unique locations into consideration. I have a few evergreens that should be called everyellows yet the computer printouts on my soil indicate everything is fine. Obviously, something isn't....

That said, it is unlikely but some compostables are unusually high in specifics like banana leaves which are chock full of potassium and egg shells/calcium, etc. Compost breaks down so slowly however, it should not be a problem. 'Tis a puzzlement.

I too would love to know how to rid my soil of these elements.

In checking the new MG manual it does mention "...phosphate ions are absorbed from the soil solution and used by plants; the soil solution is replenished from soil minerals, soil organic matter decomposition or applied fertilizers". Theoretically I guess, too much organic matter decomposition could somehow effect the amount of P. (But I still doubt it.)

Incidently, from what I can see, the book does not address an overabundance of elements.

I stumbled onto cover crop material....it seems a couple of things will help bring phosphorus to the surface, buckwheat and yellow blossom sweet clover. I have no idea if either will grow well in the southeast and I haven't ordered from this company they just happen to have both.
...an idea at least

http://www.territorialseed.com/product/1248/69

http://www.territorialseed.com/product/1249/69

I'll throw in a thought or two. First off crop producing fields are left fallow on a rotation and that might be a good idea for you Stono. Sometimes you're better off just letting things go wild for a little while. Might fix the problem by it's self. From what I remember you saying you're not on a patio lot. It might not be worth the effort to do anything. I would think planting a bunch of bananas would suck phosphorous out of the soil as long as you trashed the leaves or moved the old leaves somewhere else. I don't know what would suck up calcium but I'm sure there is a plant out there some where that would. Of course huge amounts of water would probably leech minerals out of the soil too if they're not being replaced.

Second thought is I don't doubt you have high calcium or phosphorous levels from where you are. Somewhere along the way your land was in the ocean.

Thanks guys (and gals!). I've had soil sample tests run every year for the last 20 years. Always had a high pH, but managed to compensate with applications of aluminum/iron sulphate to get it back close to neutral (7.2 was as close as I've come to neutral, but I'm still working on it). Don't want to do a "shock treatment" because it would cost us a whole growing season. Current results are are 7.2-7.8 pH for the various beds. The curious thing is the response of the different beds to the application of acidifiers in the past. Some responded quickly, some responded slowly. Kept watering roughly the same in all the beds. Some responded---in varying degrees---one didn't---which we have ingloriosly named the "death bed". That's the one we're focusing on this year...

That's kind of a surprise to me. I come in at about 5.7 ph, totally different soil. I'm not very far inland either.

one other thing, I'm not sure why it didn't occur to me but earthworms will eat up those excesses.......as attractive as coffee grounds and newspaper look in the garden, you can't go wrong there :)

Interesting, Tropicanna! I have jillions of earthworms---which I always attributed to my yearly additions of organics as soil amendments/mulch. I cheaped-out this year on measuring the organic component of the soil (losing 1/2 your net worth in a matter of months does that to you!). But in the past, readings of "organic component" of my soil always came in remarkably UNDER the mid-point, which surprised me considering my cultural practices. The whole thing has gotten way beyond my comprehension...
And CoreHHI...I've got a fairly large growth of banana's in one corner of my veggie garden. Since their growth has scared me somewhat, I've started hacking them out to retain them. But since the sample I took nearest them doesn't differ significantly from the sample furthest away from them, I gotta conclude they wouldn't help...
This one's a female dog to figure out...(reckon that will make make it past the PC Watchers...but if not, I'll find another way to contact you)...

LOL. PC watchers.

Have you tried to contact any of the real farmers around here? They might have a go idea what to do or maybe not? I'm just thinking they have to deal with this stuff for a living so they might know something. I know there are a few guys on the GA forum that grow crops for a living.

My thought was on finding something that feeds on minerals, maybe spinach??? I don't know but that's where the banana thought came from. Some plants are rich in minerals so I assume they take them out of the soil.

Good luck on your problem.

I like your thinking, Core! I've always struggled with "cool weather" crops here in the low country (particularly, spinach and Swiss Chard---two of my favorites), and have hit-and-miss success with them. Some years they produce whopper crops, some years they produce nada. Kohl Rabi seems to follow suit. .. There's a pattern here, but in 20 +years here, I haven't yet been able to decipher it...

I don't know anything about growing veggies but the green leafy ones have loads of minerals in them. Spinach and arugula are my favorites for salads. I like the more bitter greens. Arugual is bitter with a sort of a spice favor to it. My most made salad is a spinach salad with black olives, crumbed feta and onions finished with a light vinagrette. I'm trying to remember swiss chard. It's a bitter green that is usually cooked isn't it? I know I've had it, just not recently.

Stono,

all I can say is, dear, some growers would love to have your problem :) your ph is not too crazy far out of balance.....if I had your soil/zone/location, I would probably plan for lots of crinums next year or heavy blooming annuals...with buckwheat and sweet clovers thrown in very haphazardly in betweeen...lol......next year.

I do agree w/ what ardeisa and core said about location. the nice thing is that you don't have to think about fertilizing for blooms for a year or two. I don't know if y'all have had half the drought we have the past couple of years but I intend on blaming any problems I have for the next two years on the last two years drought ;) I really do think that had an effect on your soil tests

We've had drought conditions here in '06 & '07 Tropicana, but this year we've had adequate rain. All beds were under controlled drip irrigation all years, so I don't think it's a watering problem, or it would have shown up before now---unless there's some mysterious "cumulative effect" that is way over my head! And Core, Swiss Chard is totally delicious (when you can get it to grow in rhese southern climes)! The greens (cooked separately from the white "stalks", or "ribs") are loosely reminiscent of spinach...the "whites"(stalks) are a treat unto themselves. The recent popularity of "Bright Lights" variety, grown as an ornamental, is justly deserved...as an ornamental. It can't hold a candle to the veggie garden varieties of Swiss Chard taste-wise.

Got some "off-line" (and much appreciated) insight on this situation, which I'm pursuing. If I learn anything significant, I'll pass it on...

Hi Stono,

For what it's worth my ph runs oddly high here, too. About that excess calcium, I'd like to pass this piece of info along to see if it might be of use to you. It's not a recommendation, just information because I don't know what the side effects might be. Anyhow, I have read repeatedly mulching around tomato plants with newspaper can lead to blossom end rot because (1) blossom end rot is caused by insufficient calcium and (2) the process necessary to compost newspaper uses a lot of calcium. Since you have too much calcium, maybe you should start composting newspaper in the effected bed(s). What I don't know is whether the depletion of calcium is permanent or just temporary, i.e., the calcium may only be tied up temporarily while the paper is breaking down and may then be released back into the soil. Still, I thought I would throw this out there for you to consider and possibly research.

Best of luck finding a solution.

Edited because I can't type.

This message was edited Dec 28, 2008 12:10 AM

Glad to hear your pH is high, too, scutler! All I've read about since moving here some 20 odd yrs ago is the acidic of soil in the area, and I was starting to think there was some wild conspiracy thing going. The newspaper idea is intrigueing, so I'm going to try it. Only used newspaper 1 year in the veggie garden and it was so ugly my wife made me cover it with compost. I'll do a split-plot design of 6 with newspaper and 6 without, from the same seeds and see what happens. I'll be looking for small differences between the 2 crops, since organic "fixes" usually take longer to appear than the inorganic "quick fixes"... May not see anything noticeable in the first year, but I'll repeat it next year. Worth trying when you're up against the wall...

I was also under the impression that the soil here should be acidic, but I have great difficulty trying to keep my ph down to a manageable level. I must admit that until I read your thread, I was also a bit confused about this. I bought a ph meter so that I can keep a check on it more easily. The aluminum product (sulfate is it?) did not work well for me. It seemed no matter how much I put down, the ph changed very little. I've had better success with (I believe it is) an Ironite product, a liquid that indicates on the label that it also lowers ph. If you need more specifics I can look it up and give you exact info. I use that product on the front lawn since I have Centipede out there which prefers an acidic ph. I also use that product on my gardenias. Because my soil is so incredibly determined to keep a high ph, I have to dose the gardenias frequently; otherwise, the leaves turn yellow.

I don't know if this has anything to do with my ph problem, but, with the exception of the areas where I have amended the soil with tons of compost, I have an inch or so of topsoil on top of a whitish or grey clay that seems to go down forever. Some have told me it is something called 'marl' (sp?). Others say it is limestone. I have no idea.

BTW, I live in the part of W Ashley that Johns Island. I am probably not so very far from you which may also explain the similarities in our soil. I live near the river. The area behind me is a combination of forest and marsh.

As for the newspaper, I do know from what I've read several times that while it is breaking down it uses large amounts of calcium, but again, I don't know what happens after the breakdown is complete. It may give the calcium back at that time. I have used newspaper in both my flower and vegetable gardens. It makes a great, organic weed barrier. I dunk the paper in a bucket of water for a minute or so to dampen it, then put down a layer of 5-6 pages or more around the plants (making sure to overlap by 3in or so at edges if using as weed barrier). I always cover the paper with a layer of pine straw. This keeps the paper from drying out and blowing away and is much more attractive.

Good luck. I hope this helps some. You may also want to pose your original problem/question to the folks over in the compost forum to see if they may be able to shed light on the problem.

Limestone? Hmmmm. Aren't coral reefs limestone? Oyster beds turn into limestone? Just wondering about all this. I'm orginally from an area that is all limestone under the topsoil. The limestone had fossils all through it, usually snails and different shells. Well water was very filter through the limestone which made it clean except it made for very hard water. My one side of the family were farmers but they probably just grew what would grow and never did much to the soil. Just wondering if they might know something if the problem is limestone.

About 40 years ago I found some fantastic fossils in the limestone unearthed at a contruction site in Summerville. It was clearly old coral reef. You used to be able to pick up some neat old coral at Edisto too.

Pat Lanza in her book "Lasagna Gardening" advocates soaking the newspaper overnight so it gets really mushy then she alternates layers (several inches thick) using the wet paper and compost. That really worked well for me. When it was covered with mulch you never saw the papers because they never dried out like dry newsprint would. I really never tested the pH because I had done this in small spots; now you have me curious ab out the effect of the papers on the soil.

Scutler, I hear you! For a long time, I thought my pH problem was my own doing because for years, I'd been buying bulk compost from the Bee's Ferry Landfill and using that as my main soil amendment. When things started spiraling downward a few years ago, I sent off a sample of that compost (disguised as "bed #1") to Clemson. It came back with a pH of 8.9! Stopped using that wonderful inexpensive compost ($10/ton) immediately and switched to the commercial mushroom compost ($48/ton). That hurt! But I also went out into the woods next to my house and took a sample of soil that hasn't been farmed/worked/attended to in the past 100 years (called that sample "bed #2"). That one came back with a pH of 8.2. Still way alkaline. So much for the "acidic nature" of the soil in the low country. It's a vast generalization that can lead to trouble---you need to have YOUR specific soil tested, if you live in the low country! BTW, sounds like we may be neighbors from your description...in which case, we have similar problems... I'm on the Stono, just north of the bridge. Small world!

How accurate are those portable PH testers/meters? I got one for Christmas but have not tried it yet. It does PH, but not moisture (thinking about trading it in for one that does both)

Lorie in Columbia

Hi Lorie,

Portable meters run the gamut in price and in accuracy. Mine is somewhere in the lower price range. Certainly, test results from Clemson would be more accurate and more reliable. Still, empirical evidence suggests that the meter is reasonably accurate and sufficient for my purposes. I got a reading of 7.2 with my meter in an area where Clemson returned a value of 7.5.

With my lawn, my azaleas and gardenias, and with color change in my hydrangeas, I have found that the readings obtained via my meter correspond well with the results I would expect in these plants. When the lawn was yellowing and unresponsive to fertilizer and iron, the meter showed an inappropriately high ph; when this was corrected (per the meter), the lawn immediately began to green up and improved substantially. The gardenias are particularly sensitive to high ph. When they begin to yellow, the meter shows a correspondingly high ph which when corrected yields a healthy, dk green plant once more. In a similar manner, color change from pink to blue in mop head hydrangeas also corresponds well with meter readings.

I use mine for the convenience of being able to get information quickly and frequently. I recognize its limitations. Such things as moisture content of the soil, fertilizers and salts in the soil, and even temperature can effect the reading.

One thing I have noticed over the years, scutler, is that "aereating" (sp?) the soil by dragging a (rental) roller-with-spikes over it once a year in the spring has made a noticeable difference in the turf. I think it just "roughs up" the turf enough for all the nutrients/ supplements to settle in and be able to contribute before being washed away. Just a "swag", but it seems to work. Going to try using a pitchfork in the flower beds to accomplish the same goals this year

Don't forget, you are adding oxygen too and the roots love it.

Isn't it weird how the quickly the soil changes around here! I have sand and clay on my property and when we tested the pH of our pasture last year (which ends in a tidal marsh) its was 4.9! We do find lots of oyster shells tossed around, but I we obviously didn't have decades of them piled up. Like Alice said, the oyster shells have so changed the pH of many of the sea islands.

Also, if that one soil test is an aberration you may want to retest. Your results could depend upon the tester.

Jenny

Unfortunately, Jenny, the soil test for pH wasn't an aberration---it's always been been high7's-high 8's since I first started testing it. I have managed to get it down to low 7's by using copious amounts of aluminum sulphate 3x/year (double the recommended amount per application, plus one more application/yr than recommended). The excesses of Calcium and Phosphorous were new this year, and a first "excess" of anything in 15 yrs. of testing. Your observation on results being possibly related to "tester" are appreciated, and I'm testing that possibility next week. Will let you know results...