Cover Crops Garden Mulching Pesticides and/or Herbicides Residual Herbicides Soil Improvement and/or preparation

Compost – Mulch – Residual Herbicides – What You Can Do About Them in Your Garden

The problem of residual herbicides in compost originally surfaced from 1999-2000.

Certain active chemicals in various herbicides that are sprayed on pastures, grass, straw and even some fruits and vegetables don’t break down when they pass through the digestive track of cattle and/or when they’re composted. Thus, enough of the chemical remains to damage susceptible crops in your garden when you use either the resulting compost or use the straw, hay or grass clippings as mulch.

These chemicals can cause deformed plants or poor or non-existent yields. Potatoes, tomatoes, beans, eggplant, spinach, raspberries, and peppers are some of the crops that these chemicals effect.

This makes manure, animal bedding, collected leaves and grass from unknown sources, and straw/hay a possible danger rather than a desired commodity as in days gone by.

Use to Be Composting Would Do the Job for You

Along with many other folks, I long for the days when you could feel pretty comfortable about getting any type of organic material from almost anywhere — compost it — and know nature would see to it that it did only good to your garden rather than harm. A nice hot compost pile could neutralize and render harmless almost any chemical.

Unfortunately, those days are gone. Now there are poisons that make it through the compost process and stay around for years. And if we are going to protect our bodies and our gardens from as many harmful chemicals as we can, it will take a little thought and effort.

One Less Chemical is One Step Closer to Better Health

I don’t know about you, but the whole idea behind organic gardening for me, is to know what’s in my food and try to cut down on the harmful chemicals that go into my body.

Yes, it may be true that in our chemical laden society, it’s just about impossible to be completely free of chemicals. But – for every one you do keep from entering your body that’s one less your body has to fight.

You’re taking one more step toward good health rather than away from it. Thus, you increase your chances that much more to live healthfully.

Empowering Approach Needed

Some organic gardeners take the attitude of defeat. They get plant and animal material for compost and mulch from anyplace and  disregard the possibilities of what they contain. They feel chemicals are impossible to get away from — so why try? But the way I figure it — if you don’t try — you are surely defeated. Taking charge and TRYING is a much more empowering approach.

You’ve got a lot better chance if you give it some thought and then TRY to eliminate and avoid as many chemicals as you can.

One of my favorite quotes is Never let what you cannot do stop you from doing what you CAN do!”

Knowing Your Source for Compost and Mulch Material is one of the BEST things you CAN do for your garden.

Things to Look Out For:

1. Do not use straw or grass clipping that have been sprayed with clopyralid, picloram, aninophyralid or aminocyclopyrachlor. All four chemicals are in the pyridine family of chemicals.

  • You might want to read my post on Residual Herbicides for more information on where you are likely to find clopyralid and picloram.
  • Aninophyralid is manufactured by Dow AgroSciences sometimes under the trade name of Milestone.  It was created as an herbicide for pasture lands, roadsides and grasslands.
  • Aminocyclopyrachlor is the latest of the herbicides in the pyridine family of chemicals to make the news via the brand name Imprelis by Dupont.  Anything sprayed with it cannot be used for Mulch or compost because of the harmful chemicals that remain. The brand is being pulled from the market.  BUT, according to an article in Organic Gardening Magazine, Dupont has other products containing the same chemical that remain on the market.  They listed Perspective, Plainview, Streamline and Viewpoint.

If grass clippings come from homes (or any places) that are commercially maintained, they probably have this chemical on them.  Although the law requires the users of this chemical to tell the owners that this grass (the clippings) cannot now be used as mulch or for compost, in many cases (if not most) they’re not told.

2. Leaves are a great source of organic material for the garden and compost pile. Be cautious about getting leaves from places where you don’t know what has been sprayed on them or you don’t know what other materials will be with them.  (Like animal wastes.)

3. When looking for a source for manure to compost or use in your garden – learn what the animals are being fed.  Some owners are aware of the problem and don’t feed their animals things that have been sprayed with these harmful chemicals. If the farmer or owner won’t tell you what they feed, look somewhere else.

4. Commercial compost makers are not required to tell you that their compost might contain contaminated materials. And even if they wanted to tell you — they may not know until it’s too late.  Assume the worst and stay away from them. Rest assured that the pyridine family of herbicides will find their way into many a bag of compost sold.

Safer Bet Organic Material to use for Your Garden, Compost and Mulch

  • Use your kitchen scraps in your compost pile; or dig them into your soil.
  • Raise cover crops on an ongoing basis for soil improvement and/or mulch.
  • Pull weeds before they set seed and use in your compost pile or for mulch.
  • Use your own leaves or those from other sources you trust.
  • Recycle your yard debris – like dead limbs – if you have a chipper.
  • Recycle garden wastes whenever you can.
  • Use pine needles that from places that have not been sprayed.
  • Use decaying or decayed wood chips.
  • Use grass clippings from your yard or from those yards you know have not been sprayed.
  • Straw that has not been sprayed with chemicals of the pyridine family.

Final Thoughts

Fortunately, we still have many choices of organic material for our garden, compost and mulch. We CAN reduce the amount of chemicals that end up in our “organic gardens” by the choices we make.


Additional Reading

Residual Herbicides in Compost – Part 1

Residual Herbicides in Compost – Part 2

Composting  – The Whys and Why Nots

Collect Gold for Your Garden

Cover Crops – Buckwheat is One of the Easiest

Organic Gardening and the Value of Cover Crops

The following are on the principle covered in this post: Do what you CAN do.

A Trap Anyone can Fall into

Focus on What You Can Do



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  • Thanks Beppy. I sure appreciate your comment.
    Let me know what’s going on in your garden when you have a chance. I miss hearing from you.

  • Theresa, I garden in raised beds (I read your article on why you don’t). My main reason for doing so is the rock hard clay and the invasive crabgrass which is everywhere around here. If I gardened without weed barrier and the physical barrier of a raised bed – I would be weeding ALL THE TIME.

    Anyway, perhaps I’ve set myself up for this problem – I am adding three new 4 by 8 beds this year. I’m struggling to find sources of clean manure, leaves, etc. to begin building them up. I won’t use the County compost, and I’m not sure what’s in the bags at the big boxes.
    I’m pretty sure you don’t encounter this problem – but any suggestions? Thanks.

  • Hi Sandra,

    I first started gardening at our previous residence only 7 miles away. We had rock hard clay that would not drain and was so hard you couldn’t dig it with a shovel. Had I not been desperate to garden to have something to eat — I probably would have given up right then.

    We’d break up the stuff with a pick sometimes so we could shovel out enough to add organic matter to the beds.

    Each year the soil got better and better — blacker and blacker rather than orange and yellow.

    At our current residence we started with sandy soil. Now it too is black and holds moisture.

    At both places we’ve had rampant, invasive wiregrass (crabgrass). It’s stolons — as you probably know — will go through about anything including your potatoes if it were to get into the bed and take hold. It makes it way into the roots of lilies and others plants and stays forever — continuing to live — like something from a horror movie.

    Your reasons for having framed raised beds are exactly my reasons for having unframed raised beds.

    When soil is prepared properly and becomes loose and friable — which clay soil will become when you continue to add organic material — even though it remains a bit more dense than improved sandy soil — and is covered with mulch — wire grass (crabgrass) is easily kept out.

    Take my borders for instance — Wire grass goes right up to them. If I see it cross the line into a bed — I take it out.
    The soil is so loose and friable that it’s easy. I don’t make a job of it, I just do it while I’m in a place doing something else.

    Over the years I’ve pulled it out of my garden so that the edges are the only place it tries to crawl in. If I didn’t have to have a fence to keep dogs and rabbits out, I could easily keep the wiregrass from the edges of my garden as well. It’s the barrier of the fence that makes it difficult.

    Regarding your quest for organic materials: I think you are wise to avoid using County compost. I read all the time about so called organic gardeners using that kind of compost. Talk about taking a chance! You don’t know what’s in that stuff!

    Again – you are wise to avoid the compost products in big box stores. Not trust worthy at all.

    But yes – I DO encounter the same problem. Read my post for more details.

    I’m still able to get straw. Even that I’m sure is sprayed once when growth first starts, but my farmer tells me that’s the only time. Cover crops are an excellent way to improve the soil and we can grow these ourselves. And I’m fortunate enough to have enough leaves from our 4 large trees to put into my garden.

    Once every year or two years I will order a small bag of compost for special use with seedlings, etc. from Wood Praire Farm. I’ve dealt with these folks for so long and they’re organic all the way. I don’t think they would ever sell anything against organic principles. The “Compost – Potting soil Mix” is called Vermont Compost Fort Vee Potting Soil. It is a general-purpose mix for starting garden vegetables and plants. I don’t use it that way — I just add a couple of spoonfuls rather than plant in it.

    Hope you’ll find this helpful, Sandra.

  • Yes, I find this answer VERY helpful. I’m grateful for your time taken to answer. In the past, I’ve imported(bought!)every ounce of the soil I garden in – or made it from leaf mold or my own compost. Perhaps, I need to bite the bullet and start tilling and ammend. Wish I’d found your blog last Fall when leaves were plentiful! Thanks again.

  • So glad this was helpful Sandra. Leaves are gold! Literally gold! Get every single one you can when you feel comfortable about the source.

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