Herbicide Contamination In Manure and Compost

Okiedawn OK Zone 7September 23, 2008

Y'all know that I always strongly encourage gardeners to add organic material to their soil to improve its' tilth, fertility, drainage and ability to hold moisture. I encourage mulching as well. Two materials that we use to improve our gardens are compost and animal manure. This summer, thousands of gardeners in Great Britain encountered severe problems that apparently resulted from the use of cow or horse manure and/or compost. The compost and manure are believed to have been contaminated with herbicide residue. The specific herbicide in question is produced and marketed by DowAgroscience and is known as aminopyralid. When I first read about this contamination and saw the "pyralid" in the product name, my mind wandered back to the early 2000s and a similar situation that arose with picloram and clopyralid.

SUMMER OF 2008 IN GREAT BRITAIN: Gardeners began to notice distorted growth on many plants. The problem seemed most severe on many broad-leaved vegetables, but also affected some ornamental plants like roses. Tomatoes, potatoes, lettuce, carrots, beans and peas seemed most susceptible to the herbicide damage. The squash family seemed least affected. (I don't know why.) In most cases, the damage showed up as cupped leaves, distorted fern-like foliage, pale color, disorted growth with prominent veining, and stunted growth that did not produce crops.

The common thread was that the gardeners were raising crops in soil that somehow had become contaminated with aminopyralid. In some cases, they had purchased manure, stable bedding (manure plus urine-soaked animal bedding) or hay/straw from local farmers. In other cases, they had purchased commercially-bagged manure. In at least one case, the product was ORGANIC manure purchased in bags. Some gardeners found that the supposedly sterile seed-starting mixes they used were contaminated, so their plants were affected from the very start.

After a couple of months of intense scrutiny and reporting on the situation by British gardening/agriculture interests, including discussion on gardening blogs and forums, the sale of aminopyralid was suspended. I believe I read somewhere that it was the UK branch of Dow Agroscience that made the decision to suspend sale and use of the product with the permission/support of the government. However, the product was not recalled and people who already purchased the product still retain it and, presumably, have it stored.

WHAT DOES THIS MEAN FOR US? Well, first of all, aminopyralid IS sold and used in the USA, so we could see the same chain of events occur here that occured in Great Britain this summer. Therefore, each of us must be careful about the source of ANY manure, composted manure, manure/stable bedding, hay, straw or compost that we use in our landscapes in any way. Unless you are using only products raised on your own property, with no outside inputs, you have no way of knowing if aminopyralid has been used on anything that went into manure, compost, hay, straw, etc. So, be sure of your sources.

I have lots of wonderful farm and ranch neighbors who often give me hay, straw and manure, but I am careful to find out from them if it might be contaminated with a herbicide residue. If there is any doubt in my mind, I don't use the hay, straw or manure. I also only purchase bagged manure or compost from reliable sources.

Some of you have cattle and horses and use their manure in your own gardening operations. Remember that, if you purchase hay or feed for them that has been contaminated by this herbicide, you could inadvertently contaminate your own garden if you use that manure or stable bedding.

HOW LONG DOES IT LAST? I am not sure that anyone is positive. From what I read, gardeners in Great Britain were told to harvest this year's crops (if their gardens produced anything to harvest), remove the residue, leave the garden plots fallow next year (2009) and then their garden soil probably would be safe to use the following year (2010). I suppose we won't really know, though, until someone tries it. From what I remember from the similar picloram/clopyralid contamination problem in the early 2000s, though, it seems like the contaminated soil wasn't usable, in some cases, for 3 or 4 years or more. I think that Dow's own data shows a chemical half-life of aminopyralid of 533 days. No one is saying how long it is known to persist in the soil.

IF YOU'VE USED A PRODUCT CONTAINING AMINOPYRALID: If you know that you have used a herbicide containing aminopyralid and you're wondering how long your soil, hay, straw, compost or manure may retain traces of this herbicide, you probably should contact Dow directly for advice on how to proceed. Sometimes, when you have herbicide residue contamination in your soil, you can reduce its' effect by adding lots and lots and lots more uncontaminated organic material to the soil.

PICLORAM AND CLOPYRALID: In the early 2000s, these two herbicides showed up in home gardens and some commercial gardening operations in several ways. In Washington state, it was determined that grass clippings treated with these herbicides were collected curbside by some cities that ran their own composting facitilities and then sold/gave the resulting compost to their citizens. I believe something similar happened on a large-scale in Pennsylvania as well.

I believe some bagged compost or manure that people purchased in other places may have had the same issues, based on anecdotal evidence.

In numerous other cases from various parts of the country, landowners used the products on their own property and then let cattle graze on pasture land or range land treated with picloram and clopyralid. Because neither of these herbicides metabolizes in the animal's body, the herbicide residues were excreted in the animal's urine, thereby contaminating manure, straw or hay bedding, and even the ground. IF that manure or staw/hay bedding found its way into compost or was directly applied to gardens, the herbicide was then introduced to the garden where it damaged and killed plants.

In many cases, well-meaning farmers and ranchers gave straw, hay, manure and manure/bedding mixes to family members, friends or neighbors for use in their compost piles or gardens. Even after composting, the herbicide residue remained and damaged crops. A lot of gardeners found NOTHING would grow in their contaminated soil.

Finally, please understand that I am not blaming the manufacturer of aminopyralid OR picloram OR clopyralid (or similar compounds) for what happened later with herbicide residues from their products, either in the recent cases or in the cases from the early 2000s. I am confident that they did not foresee having residues of their product end up in compost or manure and affecting gardeners. I do somewhat believe the EPA to be at fault here.....if it is their "job" or "mission" to make sure that a product is safe, they need to do a better job.

I think that there are plenty of times when people buy and apply products without reading all the precautions and warnings on the labels. That is one way that chemical residues end up in places they shouldn't--because at some step in the process, somebody may have used a product in a manner that did not comply with label directions, warnings and precautions.

So, ultimately, each one of us is responsible for what we use on our plants and our soil. I just wanted to make everyone aware that aminopyralid is out there, and this problem has occurred in Great Britain. Has it happened here? Probably. I distinctly remember reading someone's posts on one forum or another this summer where they mentioned that, in the last couple of years, they'd lost their veggie garden due to herbicide contamination, although I don't think they specifically mentioned WHICH herbicide that they thought was responsible.

If you want to read more about the problems gardeners in Great Britain encountered this year with this herbicide, you can Google "aminopyralid" OR go to the bottom of the Wiki page and visit some of the External Links listed there. Wikipedia's brief entry on aminopyralid is linked below. Finally, the current issue (October/November 2008) of the magazine MOTHER EARTH NEWS has a one page article on this topic, written by two very well-known organic gardening writers, Cheryl Long and Barbara Pleasant. Their article contains a boxed quote from Shirley Murray that perfectly describes the whole issue in one very memorable sentence. I hope you'll find the article and read it.

Happy (and Safe) Gardening,


Here is a link that might be useful: Wiki entry on Aminopyralid

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This may be a little off topic, but we were visiting some friends this week and they had someone spray their pasture to get rid of the weeds. The weeds had died and the pasture was green. They were told their cattle would not be harmed if they continued to graze, but they have lost two cows since they had it done. I am afraid of all of that stuff.

    Bookmark   September 23, 2008 at 6:55PM
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Okiedawn OK Zone 7


I can't argue with you there and am, in fact, in total agreement. You see it happen all the time and you suspect the link, but proving it can be extremely difficult. A friend of ours bought her three cats flea collars from a local vet....one cat's hair in the area under the collar turned from black to white after wearing the collar for a couple of days. Another cat mysteriously died about the same time. The third developed a hormone disorder that causes him to pull out all his hair. I suspect it all was linked to a chemical in those flea collars.

A long time ago....way back in the mid- to late-1980s, I worked with a gentleman at General Dynamics who discovered his house had a termite problem. He hired a professional termite company (a legitimate national franchise type operation, not a local no-name outfit) to treat his home and yard. Apparently they used chlordane (it wasn't banned then, although, coincidentally, it was banned quite shortly after they used it at his place) and they must have applied it at a higher rate than they should have. Within a day or so, his three dogs were dead and he and his entire family were ill. To make a long story short, the company had to remove and replace the soil in his yard (down to a pretty good depth....we're talking feet, not inches), his turf grass, trees and shrubs. They had to replace all the flooring, subflooring, carpeting and furniture and drapes. I believe the house was repainted inside and out. All of this was done at the expense of the pesticide applicator.....and my co-worker didn't even have to sue to get them to do it. I think the company also reimbursed GD's insurance company for his family's medical expenses and paid the vet bills. (He and his insurance did have to threaten to sue.) I worked with him for several years after that, and felt like he he was NEVER really the same, physically or mentally. I don't really understand how the pesticide affected him and his family, but he just wasn't ever really "well" again.

After the picloram/clopyralid fiasco of the early 2000s, I thought we all were smarter. Yet, here we are less than a decade later, same type of problem, same type of chemical, same manufacturer. Didn't we learn? Hopefully, what happened in Great Britain is a wake-up call for us here in the USA to be careful and try to avoid similar problems.

Since the aminopyralid was licensed for use in 2005, we can assume it was available for use in 2006. If so, it could have been applied to pasture land and range land then. If that hay, straw or forage were used in feeding in 2006 or 2007, we could have aminopyralid in our compost/manure products already. I guess all we can do is be careful what we purchase and use. I do think that, after the early 2000s, some commercial compost and manure producers/distributors adopted practices aimed at keeping herbicide residue out of their products. The fact that we have not yet seen problems here in the USA like was seen in G.B. this year might mean those practices are working.

This type of incident is why I am so very, very careful about everything I put on my garden. I really don't like using any sort of compost, manure, hay or straw (or even mulch) unless I am SURE it is chemical-free. There are too many side effects that we know haven't even been studied.


    Bookmark   September 23, 2008 at 9:14PM
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Our soil is predominately black gumbo (heavy clay in Central Texas); therefore I have heavily amended my garden for years using compost, greensand, decomposed granite, manure, composed wood chips, peat, organic fertilizer, dried molasses, etc. I have a large garden and generally purchase the amendments in bulk when possible. I always speak with the source from which I purchase about my organic preferences. Living in an environmentally conscience area I have not had difficulty locating and using organic methods for gardening. This year I decided to plant my potatoes above ground in hay and amended soil. The hay I used was from bails I had stored outside for 3 years but I did purchase bags of manure compost and composted wood chip mulch. I did not have any bulk at the time and for convenience decided to purchase it from well recognized nursery garden supply. I have four verities of potatoes (Russet, Red La Soda, a blue from the grocery, and Kennebec) planted in 4 diameter X 4Â high wire cages to which I placed the hay, manure, and amended soil. I notice 4-6 weeks ago the curling on the Kennebec potato. I asked several master gardeners to no avail and have stumbled across this web-site: http://www.allotment.org.uk/garden-diary/261/contaminated-manure-aminopyralid-update/ Now, I believe I purchased bagged manure or mulch with aminopyralid contamination. From reading here I think it might be the manure. I pose a few questions for someone more knowledgeable than I about this issue. Can hay stored outdoors for several years hold the contamination? The hay was given to me and I am not sure of the source. Will the potatoes develop and if they do are they safe to eat? Are some crops more prone to problems with this issue than others? Should I be concerned about my organic garden? I think it is isolated to one place in my garden due to the other potatoes and crops not showing signs of contamination. I have been working on my garden for years and it is now a very rich, workable, and grow-able condition. I will probably throw the Kennebec potatoes out and remove them from my garden. Aminopyralid is ban in the UK but is it in use throughout the US? Thanks for any help you may provide.

    Bookmark   May 6, 2009 at 3:47PM
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Okiedawn OK Zone 7

I had black gumbo clay soil when I lived in Fort Worth and now I have Red River red clay soil here in OK--so I understand the huge amount of work you have done to improve your soil.

I am not an expert, just a mostly-organic gardener who tries to stay current on the issues. I'm going to run through a list of possibilities/probabilities and will try to help you diagnose your problem by asking you the same questions I'd ask myself if I were encountering this problem in my garden and I was trying to troubleshoot my way through it.

The first thing that is important is to be sure you have ruled out all the various diseases or physiological problems that can cause potato leaves to curl. I'd be sure to do rule out all the common possible causes first before progressing to the possible cause being contaminated mulch. Have you done that already? And, although it seems simple, have you checked for aphids? Sometimes a heavy infestation of aphids can make the leaves of solanaceas curl. Often, very heavy rainfall can cause leaf roll or leaf curl although it usually will resolve itself as the soil dries out. Finally, if you had a sudden heat wave occur after relatively cool weather, that can cause leaf roll or leaf curl.

Secondly, since drift from herbicides can often travel up to a mile through the air, could your plants have been contaminated by drift from someone else's use of a herbicide spray? I live in a rural agricultural area and every now and then that happens to my plants.

Third, since none of the other crops are showing damage, it does seem more likely that you're correctly diagnosing your own problem, but just to be sure....is this the first year you've raised potatoes (or anything else) in the bed that now has damaged potato foliage? And, are the other areas of your garden more established than this potato bed area, or are they just as new? In the UK, the damage was most pronounced on tomatoes, potatoes, carrots, beans, peas and lettuce.

Fourth, have you shown a damaged leaf to your local agriculture extension agent to see if he or she agrees that it looks like herbicide contamination? That would be my first step. I know that you said you asked several master gardeners, but I'd still want to get a professional horticulturalist's opinion too, if possible. You probably could take a branch with a few leaves in to a nursery that has a Texas Certified Nursery Professional on staff and see what that person thinks too.

Fifth, does your potato foliage look like the photos on the allotmet website? If so, I'd take photos of your own potato foliage to document the damage. You have no way of knowing. though, if your plants were damaged by herbicide residue in the composted manure (which would be my best guess, from one gardener to another) or the mulch. It could be the hay, but if you've had it sitting for three years, that seems less likely to me. Did you use the hay, mulch or manure in any other bed other than the potato bed. And, if so, are the other plants fine or are they sickly as well?

If you can get an ag extension agent to agree that it is herbicide damage, and you sincerely believe it to be from the mulch or the manure, I'd take photos of my potato foliage back to the source of the manure and mulch and have a discussion with the garden center manager, store owner, whoever, etc., depending on where you got the products. I don't know if they will listen to you with an open mind and discuss with you the possibility that you might have purchased contaminated mulch or compost, or if they will insist that anything you bought from them is "pure". They would be the ones to try to trace back the product to its original source and see if other contamination reports have come in. If they choose not to cooperate with you, you can't force them to, though.

I am not positive, but I think that when we had this issue in the early 2000s, the thought at that time was that 3- or 4-year-old hay treated with Grazon might be safe, but not necessarily. At that time there was not a lot of research since the herbicide product should not be used around vegetable gardens.

Here's what I think. If you had that hay stored on your property and the broad-leafed weeds nearby continued to grow and didn't die a mysterious death, then the hay probably is not the source of contamination.

I've never had potatoes that were damaged by herbicide, so I don't know if they will develop properly, but I think it unlikely. Since the plants need all their foliage in order for photosynthesis to occur and for proper plant growth to continue, I'd guess your yield will be small. Even if you got potatoes from herbicide-contaminated plants, they might not be safe to eat. There is no way to know for sure, but you might go back to the allotment website and see what they were advised to do. If the aminopyralid is left alone in the soil, it will eventually break down but I think you'd have to leave that land fallow for at least 3 or 4 years. The more biological activity in your soil, the more quickly it will break down up to a point, so I'd encourage biological activity in the soil with dry molasses and other biostimulants.

When this happened in this country in the early 2000s, it took a lot of effort on the part of some very persistent organic gardeners to get the industry to pay attention and figure out what went wrong. I don't know if you are interested in pushing this that hard, or if you just want to yank out the potatoes and move on.

You still have to make a decision about what to do about the soil in that potato plot. If it truly is herbicide-contaminated, you cannot grow anything edible there for several years. There is a product called Zeolite that Howard Garrett often recommends when you need to remove contaminants from soil, but I don't know if it is effective for herbicides. Speaking of the Dirt Doctor, you might try to contact someone through his website to see if he has received similar reports of this kind of contamination or if he, or one of the master gardeners who work on his phone lines (during the radio show) or on his website (which has forums, I think) have seen any other reports of this.

I've grown potatoes for many years but rarely have had foliar issues or any problem, except for those pesky little potato bugs, and I only see them once every 3 or 4 years, so I hesitate to say your problem "must be" herbicide contamination, but it you can rule out common potato diseases and physiological leaf curl, then I think it probably is a herbicide issue.

One way to test it....plant a handful of beans in the soil where the potatoes are grown. Plant another handful of the same type of beans in another area of the veggie garden. Watch them grow and see what happens. Compare the results between the two sets of beans. Usually, if you have contaminated soil, beans grown in that soil will show damage rather quickly. So, if you see damage to the beans in the potato plot, but not in the same variety of beans grown in a different location in the garden, then that backs up your "educated guess" that you have either contaminated mulch or compost. I would think that within 4 or 5 weeks of planting the beans, you'd know something one way or the other since the beans ought to hit the contaminants in the mulch/manure within that time frame if not earlier. If the beans grow equally well in the potato plot and in the rest of the garden, then that would make me think the issue is a potato virus or was airborne herbicide drift that, for whatever reason, hit only that section of the garden. You could use tomato plants (I'd just buy a small 6-pack at a local nursery if they are still available there) or a new planting of potatoes in the contaminated and clean soil, but I think beans would react more quickly. Oh, and I am assuming you used only certified-disease-free seed potatoes? If so, that further lessens the chance of a viral or fungal disease.

I've linked the allotment update so anyone else reading this thread can go to it if they want to read more detail about last year's contamination issue in the UK.

Good luck,


    Bookmark   May 6, 2009 at 5:44PM
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This is an interesting topic, since I am growing potatos in bins this year, but was a little short of compost, and haven't had access to hay or straw, so I've supplemented with some bags of mushroom compost from the mushroom farm in Miami, Ok. I wouldn't think it would be contaminated, but my concern was that it might be too rich for the taters?

    Bookmark   May 11, 2009 at 12:45AM
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Okiedawn OK Zone 7

The likelihood of getting contaminated compost from a commercial source in this country is slim nowadays since all the compost producers learned their lesson well when we had the problems earlier in the decade.

I don't think you have to worry about the mushroom compost being too rich. The mushroom compost starts out rich, but by the time they've grown mushrooms in it, much of the nutrition has been used up. I think mushroom compost is fantastic for adding organic material to soil to improve its texture and friability, but I don't rely on it alone for nutrition. The potatoes should be fine growing in it.


    Bookmark   May 11, 2009 at 10:57AM
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I agree about mushroom compost being fantastic for amending soil. I wish my garden was full of it. When we lived in Grove, we went to the mushroom farm in Miami and got a pickup load of it for around $25 dollars, and put it in our raised bed......(you have to have raised beds in Grove).

Anyway, the vegetables went crazy over it, and even though I crowded the plants close together, they produced beyond my wildest expectations.

Even though my soil seems to be good, as we garden, the vegetatables use up a lot of nutrients, as you know.

Anyway, about using mushroom compost in my potato bins, so far so good. I did run out of that in a hurry, since the potatos are growing so fast, so I started using spaghnum peat moss on top of it. I just wish I could find some "spoiled hay or straw" right about now to lay on top of all to give a cool place for those tubers to start forming.

Thanks for all your wonderful advice Okie dawn. I always come here when I need some garden input on any garden subject. You are a true godsend for Oklahoma gardeners!

    Bookmark   May 16, 2009 at 12:44PM
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Okiedawn OK Zone 7


You're so welcome. And, you know, I learn from all of y'all too!

My best source of spoiled hay or straw is local ranchers who store hay for winter and never quite get around to using all of it. After it has sat in the back of the hay barn for a year or two, they don't really want to feed it to their animals.

You might try posting a 'need' or 'want' on your local Freecycle website asking for old hay that isn't "fit' for animal feed but which could still be used as garden mulch. If you've never been to your local freecycle site, you might be amazed at the stuff people give away there.


    Bookmark   May 16, 2009 at 1:57PM
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Like Daw said farmers and ranchers are a good source. And whether you live in town or in the country might make a difference where you look. I never have any trouble finding it around here. I have some of my own every year from where I stack and feed the alfalfa. Then the extra I need I get from farmers and ranchers. The FFA farms around here are often a good source. There will be extra bales that didn't get used and molded and rotted. Also they have straw with manure sometimes that works well in the garden. Some feed supply stores will let you clean up what is loose around their stacks. I also get grass clippings from the local recreation department when I need extra mulch. If they spray they wait a few cuttings to let me know and it has worked well. I get the tree leaves from the lawn care services in the fall and cover them so that don't blow away and use them. Just a few more suggestions that might work for you. I have listed looking for a few things on the Craig's list sites closest to me with good results. Hope you find what you need. Jay

    Bookmark   May 17, 2009 at 10:11AM
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In the previous post I see I should of proofread. I meant Dawn. Hopefully she will forgive me. Jay

    Bookmark   May 17, 2009 at 10:13AM
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Thanks for the info y'all. I have used staw bales before that I left out to get rained on to sprout all the seeds in them, so they wouldn't sprout in my garden. Mulching potatos this way produced some of the best potatos I've ever eaten, and what fun it was to run out before dinner and dig up a few crispy fresh Yukon Gold's right out of my own garden!

Right now, since I am a single lady, my problem is getting the spoiled hay or straw from point A...the farmer or rancher's barn or whatever...to point B...my garden :(
But, I'll look around as per some of your great suggestions and see what I can come up with :)

However, right now I am preservering and on top of the mushroom compost and peat moss, I'm using a bunch of last year's dead grass clippings that I'd piled up, some of which were partially composting, and I am breathing prayers that there is no fungus in this material to affect my potato plants which are growing like crazy.

Afterwards, I lightly dusted with Bonide Copper Fungicide, which I hope will control any potential fungus, and that it won't do more harm than good.

Also, even though the plants look healthy with no sign of potato bugs, "something" seems to be nibbling the edges of some of my plants. If it gets worse, I'm going to have to fight back rather than have all my hard work destroyed by some trespassor!

Another question I have is, when do I stop adding more compost, hay, straw or other mulching material on top of these fast growing potato plants? None of them have started blooming yet.

    Bookmark   May 18, 2009 at 3:07PM
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Okiedawn OK Zone 7


If the worst thing you ever do to me is mis-spell my name, then I guess we'll be friends for life. No apology was necessary but if it will make you feel better, you're forgiven.


It is perfectly acceptable to lightly sprinkle the leaves with copper, but.....anytime you use copper as a preventive treatment, any disease that subsequently develops is likely to be resistant to the copper, so you'd have to treat it with something else were that to occur. One argument against heavy use of copper fungicides is that coppper can build up in the soil and cause problems for plants. I don't use anything as a preventive, and only have disease issues on potatoes maybe once or twice a decade. When you use a fungicide as a preventive, one thing you can do is alternate 2 different fungicides so that any disease organism present is less likely to develop a resistance to one.

Check your potato foliage for the little pink larvae of the potato bug. They will do damage long before you realize they have arrived.

I'd pile on the compost/mulch combo to a depth of about 8" above the potatoes. Research has shown that piling it on deeper does not give you larger yields....just as planting deeper than 8" doesn't give you a larger yield either.

I've linked a photo of the larvae of the Colorado Potato Beetle. I first started seeing them here about 6 weeks ago, but not on my potatoes or tomatoes.....on my daturas.


    Bookmark   May 18, 2009 at 10:44PM
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Point well taken about the copper fungicide. Thank you! I was a bit worried about using it anyway. The reason I used it was because of a slight "musty" smell coming from the dead grass clippings I'd used as the last layer of mulch, some of which was only partially composted....which spells "fungus" to me, even though it looked okay.

So far, so good though, and the potato plants are still growing well and looking healthy. But I guess I need to stop adding more mulch, which is pretty deep now, because the plants just keep on getting taller and taller. I think I was laboring under a misconception that if I added more mulch, the plants would indeed form more potatos under a deep mulch.

Obviously, I'm still learning about potato growing, but less now by trial and error since I found this Okie garden forum and a lot of seasoned garden advice from you, Dawn, and the other wonderful contributors here. Thanks once again. You quite well may have saved me from a crop failure, which is always so disappointing.

About those pesky potato bugs, I'll be on the lookout now so I can deal with them before they have a chance to do any real damage.


    Bookmark   May 19, 2009 at 12:19AM
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Okiedawn OK Zone 7


Everyone thinks that with potatoes, the deeper you plant them or the higher you pile the mulch, the more potatoes you get. It is a very common misconception.

About the copper.....it is a great fungicide, but you always have to be worried about preventive applications of any fungicide eventually contributing to "super" strains of fungus and bacteria that are resistant to the copper. It is the same issue we have in the human/animal world where diseases become resistant to commonly-prescribed antibiotic medications.

I don't think your crop would have failed under heavier mulch, but it just would have been a wasted effort to keep piling on more and more.

We all learn from one another here, and I love that.

I think all gardeners are essentially scientists who teach themselves how to garden through experimentation. Think about it.....we try to grow something one way and, if it works, the "experiment" is successful and that way of doing things becomes a part of our routine. If that method doesn't work, we conduct another "experiment" when we try something else. Through many years, and lots of experimentation, we arrive at methods that work for us. To me, this forum helps us share the results of our own experimentation and saves us from completely reinventing the wheel by enabling us to benefit not only from our own experiments/experiences, but from those of all who post here.


    Bookmark   May 19, 2009 at 9:17AM
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Lab confirmed aminopyralid garden poisoning here in SE NC. It's out there. It is persistent. I would love to see the actual report of 533 day persistence. Dow Agrosciences only refers to a 30 to 35 day half life of residual spray in soil on sprayed fields. Since my exposure came from manure - hay that was ingested, digested & excreted in glycoprotien-bound chunks, I would love to get documented data on persistence in that form.
For folks willing to test using the pea test - beware. Peas shoe symptoms/croak off at 200 ppBILLION while tomato plants are knocked off at 3 ppb. So even if the peas survive there may be enough aminopyralid (or its cousins) present to sicken/kill tomato plants for many half lives. So my question is : Where's the documentation on t1/2 for aminopyralid in manure in & on soil?
Mmmmm, yeah.
Interestingly a friend who suffered the same experience was told his wonderful (absolutely gorgeous) cabbages were fine to eat by the company rep - the same feller who declined a wedge of said gorgeous sweet cabbage...Mmmmm, yeah, it's just a fine product...

    Bookmark   June 21, 2010 at 3:25PM
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