I use horse manure and have done so for decades and never had a problem. The stories all originate from the same (one) problem at least 10 years ago.

If you're concerned you might buy bulk mushroom compost. I suggest that as this product was previously used to grow two crops of mushrooms so should give you a little more confidence about using it. From my experience you can fill your own bags at some garden centers that sell in bulk. You'll have to fill your own bags.

The largest grower of mushrooms uses manure from facilities that use cocoa hulls for bedding in the stalls. But they're near Philadelphia which is kinda far from you to expect that that's the source of what you're buying locally.

You ought to check with your local garden center/nursery. Many of mine around here have straw for that purpose, and I'd like to believe they've checked the bales out for optimal growing. Same with compost. I'd never get those things direct from a random farm. Herbicide contamination of farm products is actually pretty common.

Mushroom compost is really popular and common in PA, as we have a lot of old coal mines in which to grow mushrooms.

No, seriously, that's what we use them for. However, that stuff is often treated to assure that nothing grows other than the desired fungi. It's usually...not exactly what I'd be inclined to call perfectly organic. You have to check to see exactly what's been used on it. Aminopyralids are a listed potential contaminant (do a quick Google search).

Really, I think you're going to have to call and see specifically to each compost source and either take their word on it...or not.

Ask for testing, if available, and certifications. Those should give you some peace of mind, at least.

True straw hay (small grain) will not have those chemicals in them. It is the grass hay such a Bermuda or Bahia that may have those chemicals applied. You may have to call the sellers of hay and ask what they sprayed to control weeds. Some of the lower quality grass may not have had any herbicide applied.

Those persistent herbicides are commonly used with pasture grasses. They are also commonly used with grain and cereal crops. With the exception of golf courses and some municipal/utility right of way maintenance, those are the only approved usage of these chemicals. Their use by homeowners or for any residential application has been prohibited since 2005.

So by inference, both livestock manures and bedding and straw could very well be contaminated. Just this summer there was an issue of contaminated steer manure and mushroom compost being sold (unknowingly) by two landscape supply outfits in Oregon. The problem is more common than you would suspect.

Ask before you buy and test before you use. Bioassays are pretty easy to perform and should provide the assurance you want.

I'd be careful. In my neck of the woods, hay straw is routinely sprayed with Harmony and 2-4D, and carryover is well known. That being said, the half-lives of these herbicides is a month or less. So if you use them after a year or so, the risks will be minimal.

One thing that came to me this evening while finishing up and wrapping was that you have to have any number of organic farms, large and small, in your area (I certainly do!) Give them a call and ask either where they get their organic hay and compost, or ask if they sell (or would be willing to sell you the small amount you would need).

You might be able to piggyback off their research and benefit them at the same time with a small sale if you buy from them.

(It just so happens that, while wrapping, the episode of American Dad where Hayley takes an episode off college to raise money for charity by opening an organic mulch farm was on this evening, which is what made me think of it. Silly, but there it is).

In situations like this, the law of incentives pertains. That is, a given farm cares squat about keeping you as a small customer. They don't need to take a lot of care in making sure they don't give you tainted materials. They care enormously about keeping nurseries and garden centers as customers, because those are big customers. That's why getting such products from nurseries and garden centers is a likely safer option. They will add a markup to the price, but you get what you pay for.

Dan, I looked up the label on Harmony and it showed that you could plant cotton 14 to 21 days after application, and all other crops could be planted 60 days after application. If you are using the straw cut in the summer of the previous year, I would think Harmony would be broken down enough not cause a problem. Just a thought, not research. They do not grow small grains around here and its been over 20 years since I was in an area that planted wheat or oats. Not sure what they are spraying now.

The problem with picloram in manure is it is concentrated and pretty stable. The concentratiions are not as high in hay. But still might cause problem, not really sure.

If you could find bailed organic rice straw that should work well. I would not use conventional rice straw. They add some pretty strong herbicide to control weeds that might have carry over in the straw.

Yes, that's right. As I say, the half-life for these particular herbicides is short, and certainly, if you put the stuff aside for a few months, they'd be good to go after that. But other herbicides are much more long lasting. Aminopyralids and picloram can take a year, if sunlight isn't hitting them.

If the hay producer is only using roundup (on bermuda grass hay) or 2,4d, there should not be a problem with planting since both of those are only contact herbicides. They do not have any pre-emergent control.

Agreed, but the OP did say they were looking for "herbicide free" straw and compost. They'd have to chime in on whether "no pre-emergent control" would be good enough.

I plant pretty much as soon as the glyphosate is completely dry, so for me, yes. :-) For somebody looking for pure organic, probably not.

I might add that some herbicides, like glyphosates, bind tightly to soil colloids. As a result, if the straw bales are just being used to border a bed, which is what the straw bale method is all about, that herbicide might not migrate very far into the bed itself. That is, the straw shouldn't be used IN the planting mix. Aminopyralids and 2-4D are more water soluble, however, and could contaminate groundwater. So, it depends.

Exactly. But we still haven't heard from OP about how far they're willing to flex from that "organic" stance. From the core argument, it didn't sound like much, but I could be wrong.

Like I said, I'll drop something on top of glyphosate, and 2,4-D isn't of great concern to me either. I use things judiciously at minimal levels and only when required (I'm IPM with a least-toxic approach and a strong lean toward organic where possible). And enough of a chemist to read a breakdown chain and understand residence times and the toxicity of the resultants, if only with a lot of help sometimes and a couple e-mails and vid calls to friends. :-)

But kudos and love to those who prefer a more organic route than I do. :-)

I avoid straw on principle (even the weed free stuff has weeds and its own seeds in it no matter what), but do use ecologically-sourced Canadian peat moss. Yes, that ecologically-sourced bit is...questionable, but it's better than nothing!

And a Merry Christmas to you as well.