What kind of organic matter to add to sandy soil?

Hi,

My soil is sandy, but all of my plants are fine, except some of the veggies. I don't need amendments--there's plenty of nutrition in the veggie garden soil--I had it tested. I need organic matter. But what to get?

I thought compost would be best. My gardener's group pointed me to a local supplier who offers equine-based manure that's been "cooked" so there aren't any seeds. She recommends combining this with compost she gets out of state, though she hasn't said what that compost is made from. Wouldn't I hope for some made from regular-old food scraps? Manure alone doesn't seem right.

Is there another kind of organic matter you would recommend?

Also, any tips on how to add it in with the least amount of disturbance to the soil structure--or is disturbing the structure just unavoidable when you're trying to change the soil's consistency?

Many thanks,
Shayna

I use grass clippings and shredded leaves because that is what is available to me. When I first created my beds I dug them down deep and added lots of compost. However, if you already have your beds made and you have perennials in them you might want to just use compost on top in a two to three inch layer and let it gradually work down into the sand. That will take years to have much effect. You might want to just work a small portion of each bed at a time. That way you can dig deep mix in the manure or compost or what ever organic matter you have available, that will create a much faster fix to your soil structure problem. It just depends on how big a hurry you are in, how much organic matter you have available and how good of shape your are in physically to get all that work done. To me that is one of my favorite parts of gardening (making new beds). I know to most gardeners that is more often the least favorite part of gardening. I think the manure will be a big benefit to retaining moisture in your sand, leaves and grass clippings eventually make for great moisture retention but it will probably take them a year or more to reach that state.

Agreed.
Since your fertility is good now, you ail want to add organics to keep that going and help hold moisture etc.
Soil structure won't be harmed by working with hand tools.
The organics will improve structure by making it 'crumb--lier"

>> Is there another kind of organic matter you would recommend?

Since you can get clean manure, you have many options. It is richer than you need, in terms of NPK. Since you mainly need to add humus, organic matter or "carbon", you could use one yard of manure to compost two yards of shredded paper, dry leaves or sawdust into exactly what your soil needs. I would urge you to use some of that horse manure to make a compost heap as soon as possible, so that, this fall, you have several cubic yards of black gold to mix into the veggie beds - three or four inches would not be excessive for sandy soil.

(I think that some deep turning is beneficial while first establishing the soil in a bed. Once it is rich and organic for the first 12-18" deep, you can change over to no-till or seldom-till.)

Right now, you don't want to dig very deep anywhere you have crops already growing. You could rake any mulch aside, then top-dress with an inch or so of crumbled or screened manure. Then return the mulch to keep the manure layer it moist and digestible and attractive to worms. (Screen it or crumble it before applying because big lumps will just dry out and imitate rocks.)

OR, lay down 1.5-2 inches of manure and gently and carefully rake it in an inch or two, and deeper between rows where few roots have reached. It will benefit your soil faster if it stays moist and soil microbes are well mixed into it. Worms will also process it faster if it's mixed with soil and stays moist. Spreading any coarse mulch back on top will help everything stay moist and alive.

Until your sandy soil is richly organic, you might want to add 4 inches or even more of compost per year. Two inches in fall and two more in spring would be wonderful. Established beds that you can't turn will benefit from an inch or so top-dressed, two or more times per year.

Say your beds total 100 square feet, and you want 2" of compost twice per year.
100 sq ft x 1/6 foot = 17 cubic feet = 0.6 cubic yards.

Compost shrinks by a factor of 3-6 or so as it is pre-digested and converted into beneficial soil organisms, so you might start with a heap as big as 2-4 cubic yards. Or more likely, every 6 months start a heap with 1-2 cubic yards.

If you can scrounge dry leaves or straw or pine needles or shredded paper or sawdust to go with the clean horse manure, you could multiply the vlaue of the manure by a lot.

This is all great info. I really appreciate the specific options/instructions, measurements, etc.

When I wrote the first post, I didn't yet know how much the compost/manure would cost--the supplier hadn't gotten back to me about that. As it turned out, the price is much more than I expected, so although I haven't totally ruled out splurging on it, I'm looking for other options.

Our town makes its own compost available to residents for free--and there's lots of it. I've used it for shrubs, but have been afraid to use it for veggies. I just sent it out to a lab for testing. It's not like they can guarantee that there's nothing creepy in there, but maybe I'll be reassured somehow. I'll call the town, too, and try to learn more about their composting process. I'll get back to you and let you know what they say.

(One thing I can see for sure, though, is that there are many very small pieces of twigs and leaves in the compost, so compared to the compost I make myself, it hasn't cooked long enough. Still, as I say, the pieces are very small and should probably degrade quickly in the sunny garden. I'm not sure what to make of this factor, though. Any thoughts?)

The small pieces of twigs and leaves will create good drainage.

Sounds good to me, Shayna and Seedfork

Maybe ask for twice as mucxh of the free compost as you n eed right away. Use half, and compost half.

>> It's not like they can guarantee that there's nothing creepy in there, but maybe I'll be reassured somehow.

Assuming they use biosolids fvrom the town treatment plant, they were requried to put it through many tests to prove that their proc ess is w orking and prodcuing "Class A" biosolids. Pathogens and heavy metals have to be below certain fussy limits. Then youre town composter puts it throug h even more composting . I understand the creepy factor, but I think it is very safe unless your town engineers are brib ing the state or federal inspectors .

Farmers who sell to supermarkets can buy Class B biosolids, and use their judgement. Recently a "Food Safety and Modernization Act" imposed more prceedures on farmers usin gt biosolids or, I think, animal manure.

So even if you use town compost, or biosolids straight from t he treatment plan t, youer own crops are probably safer and cleaner than what you get from t he supermarket, wrapped in plastic.

I still wash veggies. But I thnik I'm at more risk from strangers sneezing on me than from veggies.

Hi Rick,

Getting info from my town's Department of Public Works, where the composting is done, is no easy task. However, it seems that no biosolids are involved at all. The compost is made entirely from our town's yard and leaf waste collection. In other words, it's leaves, grass clippings, twigs, etc, that have been composted by the town.

I suppose this means that my only concern is whatever fertilizer, herbicides, etc., people might use on their lawns and gardens. (It's not a fancy place where people all want perfect lawns, but I'm sure plenty of people use stuff that I wouldn't--and that I certainly wouldn't use on veggies.) Do you have an educated guess about how long residue from these chemicals might last or how much they could seep into my vegetable plants? I've had an organic garden up to now. I'm OK with having it veer somewhat from that, but I don't want it to be really questionable.

Also, I had a soil test run on the compost and all nutrients were in the very high range. Lead and aluminum were both very low. % organic matter was high.

I would love to hear your take on what I've learned so far about this compost.

>> Do you have an educated guess about how long residue from these chemicals might last or how much they could seep into my vegetable plants?

I think the answer depends 100% on who you ask. Me, I would guess that SOME people (say 1 in 20) used lots of whatever whatever they bought at Home Depot or a hardware store. And some might use a lawn service that uses the nastiest things they can buy legally, and that might be worse then most farmers.

But any chemical sold today has to be licensed, and it is diluted by 20 nieghbors who DON'T spray recklessly, and has had a long time to break down and leach away. I wouldn't worry, even on my vegetgables. But people aiming for organic certification, or that level of naturalness, probably can't use no-pedigree compost.

MY belief is that this level of caution goes beyond anything plausibly supported by science. On the other hand, science produced Agent Orange where the 2,4,5-T was contaminated with REALLY toxic 2,3,7,8-tetrachlorodibenzodioxin (TCDD - note the final "D" stan ding for "dioxin"). So I don't bkame anyone who is sceptical about scinetific claims.

I might naively believe that the really nasty, toxic, persistent herbicides and pesticides really have been phased out so much that no one can get their hands on them legally. If that were true, the things that homeowners and landscaping companies CAN still buy and apply break down faster and were less toxic to begin with than thin gts I grew up with.

They would mostly break down in the lawns and during composting. In fact, I wouldn't worry (myself) about compost I could buy locally from Cedar Grove. I don't buy it becuase it's mostly schredded wsood, yet still expensive!

P.S. If I ever bough land in farm country, I would test the soil where I put my veggie beds for arsenic. They used to use that, and I'm pretty sure it never decomposes,

However, many people are as worried about modern, relatively benign herbicides as we SHOULD have been about 2,4,5-T and 2,4-D!

And/or they just don't believe studies that measured how fast they broke down, or how toxic they are, their breakdown products are, and the contaminants formed during manufacturing are.

And/or they know that modern 'cides ARE 25-100 times less dangerous than traditonal agricultural chemicals, and they still passionately avoid the lesser risks or hypothetical risks. If the goal is to have NO risk of ANY artificial chemical getting into your food, you certainly can't use commercial compost - or go to a restaurant, or a supermarket. Even organic food stores can't guarantee NO contamination.

It's all degrees of risk, degrees of distrust, and perceptions of risk.

I think that even the most ardent organic zealot would admit that when RoundUp is used reasonably, the result in the food is dozens or hundreds of times safer than standard practices were in the 1950s.

I guess not everyone would agree that actual levels of pesticides and herbicides in supermarket food are measurbaly lower than cause detectable short-term toxicity in animals or humans. Maybe the alleged, legal levels of 'cides cause no measurable short term harm and food suppliers cheat, or the short term harm is there and scientists lie, or the short term harm is too subtle to measure and the long-term harm is real but not measured. Or it's a paranoid concern.

Or it's reasonable to want a little saftey margin beyond "scientists like those the tobacco industry hired say this food won't kill me QUICKLY".

Plenty of reasonable people would rather pay twice as much to be fairly sure they are getting slightly less RoundUp residue in their organic food than they would get at Safeway.

Or they disbelive FDA and other scientists and think there is even more residue in supermarkets "than we are told".

Or they worry about effects more subtle and longer-term than science is yet able to measure.

So I think it comes down more to "who do you trust" and "what do consider acceptable", than educated guesses.


I would use compost made from yard waste, but then, if I could get my hands on a truckfull of lawn clippings from yards that were not certified organic , I would grab it in a second. Even if most of it came from just a few yards, and was not diluted by the whole town's average herbicide usage.

But I would put it in my compost heap, not mulch the Bok Choy with it.
And I would sprout some peas in it - peas seedlings are very sensitive to herbicides.
And I'm an old guy who WAS exposed to 1950's food, and I'm not an expectant mother.

And I worked in the chemical industry, so I know what REAL toxicity is!
That may have deconditioned me so I'm not as risk-averse as some people are.
I know I won't live forever, no matter how carefully I eat.

>>And/or they just don't believe studies that measured how fast they broke down, or how toxic they are, their breakdown products are, and the contaminants formed during manufacturing are.

>>And/or they know that modern 'cides ARE 25-100 times less dangerous than traditonal agricultural chemicals, and they still passionately avoid the lesser risks or hypothetical risks.

Or, like me, they haven't read all the studies... though they are not ignorant, either...they find it hard to keep up with everything...so they struggle to find some way of making a sensible decision. Thus, I do appreciate your food for thought...no pun intended.

I must admit that given your self-description of growing up with 1950s food, knowing what real toxicity is from working in the chem industry, and not being risk-averse, I was a bit surprised to find you saying that nonetheless, you would compost the town compost before using it as mulch. That seems like a most telling statement.

In any case, I'm with you on not expecting to live forever. I don't think the way I eat will prolong my life (given my particular genetic conundrum); I do hope it might help reduce some of the illnesses/symptoms I acquire along the way.

Thanks again for your help.

Rick, When you talk about testing farm soil for arsenic, you must be talking about old orchard and market gardening soils. I grew up on a Midwestern farm and I don't ever remember using arsenic. I do remember some wheat seed treatment with some form of mercury I believe.

>> working in the chem industry, and not being risk-averse, I was a bit surprised to find you saying that nonetheless, you would compost the town compost before using it as mulch. That seems like a most telling statement.

Oh, maybe it just means that I'm schizophrenic enough to combine some paranoia with a lot of complacency. ;-)

Sometimes I'm embarased too admit in a garden forum that I don't think that the glyphosphate's gonna kill me. The attitudes do sink in, and I'm more inclined to pamper my plants than I am myself.

>> ... arsenic, you must be talking about old orchard and market gardening soils. I grew up on a Midwestern farm and I don't ever remember using arsenic.

When I first rerad "Silent Spring" in high school or junior high, I thoguht it was overly alarmist. Now I think it was true in its time, but if the smae book were publishe4d today, it WOULD be a little alarmist, if it was talking about actual toxicity from chemical pollution - we HAVE cvleaqned up ourt act a lot. If it were written today about loss of crop genetic diversity through market forces, I would buy sevral copies and try to give them away to people.

I have a great gardening book, "Complete Book of Garden Magic". The second edition was 1956 and the first edition was (I think) early '40s. Maybe I am thinking about advice to home gardeners for dusting flowers with arsenic and nicotene powder, not farm crops.

I think that Arsenic is forever. But those old-school, persistent chlorinated herbicides might linger for 50 years - or not, maybe that is paranoid again. Now those were REAL pollution!

I always thoguht it was "cute" that there were some organo-phosphate insecticides that came from WWII nerve-gas research. I can just imagine the board room discussion:
"This Geneva Convention menas we'll NEVER make our research investment back! "
"Say, JB, how's about we market it as an insecticide? This s--t kills EVERYTHING!"

I remember in the mid-1950s, low-flying planes sprayed our whole suburban town with DDT. We were warned, casually, not to stay outside and breath it in while it was falling as a gentle rain from heaven.

As a boy scout, I was told to bring a canister of DDT with me on a canoe trip in Maine. "Go into your tent, zip the mesh closed, and then spray the DDT until the insects in the tent were dead".

So I may not be a good person to make realistic estimates of actual medical risk from toxic chemicals. The DDT may have rotted my brain.

But when Mom wanted me to sprinkle dust around the foundation to kill ants, I read the label.

###!!%^&***!!!

I came up with a filter for my mouth, wore gloves, and REALLY tried to stay away from that stuff. I won one argument as a kid: we were NOT going to sprinkle any of that INdoors! They laughed at me but I stand by that decision! It ws Malathione or something worse. Isee it's still for sale! Oh, well, the LD50 is around 2 GRAMS per kg, so it isn't the WORST toxin in the world, but it's bad enough. Yup, organophosphate, cholinesterase inhibitor, not good for children and other living things. At least it isn't very persistent" "Biodegradation in soil is rapid with 80-95% biodegradation detected in 10 days."

http://msdssearch.dow.com/PublishedLiteratureDAS/dh_0060/0901b80380060a74.pdf?filepath=/011-10176.pdf&fromPage=GetDoc

>> they struggle to find some way of making a sensible decision.

Me, too!

>> Or, like me, they haven't read all the studies

Who can? Even when that's your full-time, paid profession, it's always hard to keep up with the literature in your field. It's also hard, un less you know the players, to know who has what bias, and how far they'll go to slant a study.

Everyone believes that research teams that work for Monsanto report whatever Monsanto wants said. But lately I have started thinking that there are teams "on the other side" that slant what they say to sound alarming.

I tried to read one thing that called itself a scientific paper, titled to be about about amounts and effects of residual something-or-other in food products. I had to give up after 3-4 pages of the authors ranting about "western diet" and obesity. In those pages they never went NEAR a measurable fact or provable claim. It was pure, opinionated rant.

Even if they did any lab work and reported it after the tirade, I would not trust the conclusions of anyone who rants that much in what they cliam to be a sicnetific paper. Now I wish I remembered the name of the "journal", because I should have filed it in the same mental category as Monsanto's PR releases: do not trust, obviously willing to say anything to grind their axe. Propaganda, not honest research. Not even TRYING to be honest. In fact, noot even trying to APPEAR impartial. Self-convicting.

I don't think that every self-so-called scientist is a bald-faced liar, but even people who try to be balanced are influenced by their beliefs and their research goals. When your grant proposal is to "measure the toxic effects of XYZ", you sure do pick experimental conditions where there ARE toxic effects and they are easy to measure repeatably.

Are those REASONABLE, real-world conditions? Maybe that would be a goal for some future grant.

But how can you tell unless you know the players as well as the science? I try not to form fixed opinions based on single studies, but rather on trends and wide-spread consensuses. All the researchers in a field (combined) know who the hacks are, where the bodies are buried, and who owns whom. Eventually they are embarassed to support the obvious liars (unless the ONLY funding in that field comes from liars like the tobacco industry).

And I admit: I will use the "argument ad hominem". Every time I read an obvious lie or BS by one side, I add a heavy wieght to the side of the scale that says they are wrong. If the facts supported them, they would be spouting facts, not lies.

An d every tim e I read about a person or team that used to push one side, but then admitted they were wrong, and why, I put a really heavy weight on the side of scale that beleives them. An admission contrary to self-interst and and damaging to ones own ego carries a lot of weight!

Rick, I agree with all that completely, well said. To give a simple answer to how long for the pesticides and herbicides (non residual type) to break down, three months I think is given as the easy answer.

http://www.saskwastereduction.ca/resources/Composting/herbicide-in-comp.html

This message was edited Apr 20, 2013 7:39 AM

Thanks, I felt like I was ranting a little. Everyone's entitled to write editorials and climb up on soap boxes, but it seems self-defeating to call something a scientific paper and then spout page after page of opinion, preaching and diatribe.

It not only shows strong bias, but also alienates the alleged intended audience, people looking for impartial research results.

Also thanks for the link. It's good to be reminded that some persistent herbicides are still out there. Say, I always thoguht pea seedlings were most senstitve to herbicides. But I just did a very little searching, and I saw "beans" more than I saw "peas" for testing compost for herbicides.

What do you think?

Rick,
I have seldom felt the need to test, but I did a few times when I first started picking up grass clippings, but I used tomato seedlings.

http://www.walterreeves.com/tools-and-chemicals/bioassay-testing-manure-and-hay-for-herbicide-contamination/

I guess that may be a southern thing.

Great link! "beans, peas or tomato seedlings".

I wondered about how to test clippings. layer them on top of the test pot.

And I might not have thought of his point about not letting water wash out the bottom of one pot and in to another. Cross-contamination!

Rick, I am really enjoying your reminiscing about how bad the chemicals were as compared to now. I am now 76 and it reminded me of my first paying job - I was 13 yrs old and mowed a neighbor's lawn all Summer but I also had to fight the chinch bugs in her St. Augustine grass. I got to spray at least once a month with chlordane +BCH (I think those are the 3 letters) with one of those sprayers at the end of the garden hose.

I remember my lips tingling but they haven't fallen off yet.

Paul

Chlordane: not good for children and other living things!

Sometimes I think that people who've worked in the chemical industry have a very different concept of "toxicity" from people who worry about organic vs 'inorganic' food, or modern pesticides. To me, "toxic" means my hair falls out in the shower (caustic) or a Class 5 carcinogen (airsuit or breathing mask and Tyvek coveralls). Toxic is 2,4,5 T and Agent Orange.

Roundup / glyphosphate just isn't in the same category. I'd wear gloves and a mask if I applied it, but I'm not very concerned about micrograms possibly getting into my cane sugar or soybean oil.

(But encouraging genes to jump around by shooting everything in sight with Agrobacter plasmids ... that might oor might not be reckless, but there might be a good SF novel in it.)

When I got Guillain–Barré syndrome (an auto-immune thing unrelated to chemical exposure), its uncharacteristicly rapid onset and loss of peripheral muscle control made me think "organo-phosphate or other neural poisoning" before I was given a diagnosis. I had to think of all the places I'd worked and things I might have been exposed to ... not a short list!

I think sensible people who did NOT grow up in the 30s or 50s might have better perspective on toxins than we do. Maybe it is worth jumping through hoops to reduce your risk of something detectable ever happening from 0.002% to 0.001%.

THEY aren't workiing in an industry where a medical friend of mine did some followup phone calls and couldn't reach a lot of older ex-employees becuase they had mostly died of bladder tumors (benzidene) . Benzidine isn 't made in the USA any more, but its younger more user-friendly cousin di-chloro-benzidene is what we made there. DCB is still a Class 5 carcinogen, just not as bad as benzidene. For perspective, that plant also used railroad car-size tanks full of phosgene, and hydrogen cyanide was a side-product or ingredient in one of the processes. But what you were sually more concerned about were caustic leaks, or nitric acid, or hot HCl fumes.

So I just lost ALL my prior credibility (if any) on the subject of toxins. But it is som ewhat possib le that many people today are as OVER-concerned as people 60-70 years ago were UNDER-concerned.

But it is som ewhat possib le that many people today are as OVER-concerned as people 60-70 years ago were UNDER-concerned.

Read more: http://davesgarden.com/community/forums/t/1305164/#ixzz2RFQDwiqI

I agree.

Back in 1950 when i first started spraying trees with a hydraulic sprayer, (you spray up and what doesn't stick comes down on to you) we used arsenic of lead for chewing insects and nicotine sulfate for sucking insects in combination. Later we switched to modern insecticides, DDt and Malathion, same process. Not sure how many years i did that but I can't see where it harmed me. And my children grew up healthy. Of course that was on trees on home properties and estates, not where food was produced, but I think i absorbed some of that through my skin.
The thing i took from Silent Spring was about a third of the book was references and many were repeated and some were taken out of context.

Do I have medical problems, sure but today I rode my bike 2.5 miles for the first time this Spring. Wednesday i will go to the gym to exercise for over 2 hours and Fri i will do it again i haven't taken antibiotics for over 4 years.
I rode my bike 2.5 miles for the first time this Spring. Wednesday i will go to the gym to exercise for over 2 hours and Fri i will do it again i haven't taken antibiotics for over 4 years.
Hermna

>> arsenic of lead

Nice stuff! If the arsenic doesn't get ya quickly, hang around for the lead poisoning.

>> Not sure how many years i did that but I can't see where it harmed me.

I go back and forth on that. Sure, it disproves a lot of the very alarmist BS, but not the more thoguhtful concerns. When we grew up, things were more real, at least the things that5 people worried aboutg were more im mediate and concrete.

But I have smpthay for the modern desire to avoid provable or even probable long-term, relatively subtle harm to a small percentage of people.

But some people seem to expect to live forever in perfect health, and it must be someone's fault or something's fault if they don't.

Should we jump through hoops and double the price of food to remove hypothetical risks in the absence of any evidence? Not in my opinion.

How about weak or dubious evidence? Opinions differ.

How about this scenario: say we increase the price of USA-grown wheat so high that poor nations having a famine can't afford it, and tens of thousands starve? In some parts of the world, that's reality.

By increasing the price of wheat, there might be less gluten intolerance causing sicknesses. Also, dog is fine now that I stopped buying dog food with wheat in it.

Then why is there so suddenly [seemingly] so much glucose intolerance? Are people short on protein enzymes that should help clean up protein abnormalies?