Does grass-legume hay mean herbicide-free?

Hopefully you are aware of the need to investigate any hay you may buy for the presence of persistent herbicides. These herbicides, namely atrazine which is by far the most prevalent, seem to affect broad-leaf plants (i.e. not grass). So, if you spread it on your garden to grow anything that isn't a grass, it might kill or at least stunt your growies. I suspect I've unknowingly used such hay for mulch in my early days of gardening.

However lots of hay I see is a mix of grass and clover or alfalfa. Shouldn't this indicate that broad-leaf herbicides weren't used? I also assume that even glyphosate shouldn't be present because I don't recall there being roundup-ready pasture grass or clover available. There is roundup ready alfalfa now but that's only possible if you buy pure alfalfa hay.

I suppose it's possible for there to still be some herbicides but they didn't quite kill the legumes. However if there are a lot of legumes and they look relatively healthy surely this is a sign of no herbicides, even more so if there's other "weeds" in the hay. Does this sound right? I want to use a bunch of leftover hay for mulch/hugelkultur this year so I want to be sure.

Nate Davis wrote:I suppose it's possible for there to still be some herbicides but they didn't quite kill the legumes. However if there are a lot of legumes and they look relatively healthy surely this is a sign of no herbicides, even more so if there's other "weeds" in the hay. Does this sound right? I want to use a bunch of leftover hay for mulch/hugelkultur this year so I want to be sure.

It's always "thin ice" when discussing this, but it's a practical fact that we have to deal with potential contaminants.

Personally, I think you're doing the same visual checks I would do. If the mixed grasses and broadleaf plants look like they were pretty green before baling, I can't think of a reason to believe they've been sprayed with herbicide.

I don't have access to hay, only wheat straw and that might have traces of The Unspeakable Molecule. Before using it for garden mulch, I ferment the bale in a tub that has water, living dirt and compost tea. Haven't had any problems. This also seems to kill of latent mold spores.

Douglas Alpenstock wrote:

Nate Davis wrote:I suppose it's possible for there to still be some herbicides but they didn't quite kill the legumes. However if there are a lot of legumes and they look relatively healthy surely this is a sign of no herbicides, even more so if there's other "weeds" in the hay. Does this sound right? I want to use a bunch of leftover hay for mulch/hugelkultur this year so I want to be sure.

It's always "thin ice" when discussing this, but it's a practical fact that we have to deal with potential contaminants.

Personally, I think you're doing the same visual checks I would do. If the mixed grasses and broadleaf plants look like they were pretty green before baling, I can't think of a reason to believe they've been sprayed with herbicide.

I don't have access to hay, only wheat straw and that might have traces of The Unspeakable Molecule. Before using it for garden mulch, I ferment the bale in a tub that has water, living dirt and compost tea. Haven't had any problems. This also seems to kill of latent mold spores.

Interesting how you ferment your straw. I know glyphosate breaks down much quicker than other herbicides, especially in healthy soils. It honestly seems the lesser evil in comparison to atrazine. That stuff is nightmare fuel to me.

Another thing people will do is a germination test. They mix the hay/straw with good soil and sprout some seeds in it. If the seedlings struggle then that's a sign of contamination. If they look green and vibrant as can be then it should be okay.

Nate Davis wrote: It honestly seems the lesser evil in comparison to atrazine. That stuff is nightmare fuel to me.

Yeah, I hear you. There are several persistent varieties on the market and while they're not as widespread on hay fields up here I'm really cautious. I can get free horse dung right down the road but I don't know the source of the hay. I also know that utility corridors use that stuff (they offered free application under my power line, in sloping and sandy soil -- yikes!).

Douglas Alpenstock wrote:

I don't have access to hay, only wheat straw and that might have traces of The Unspeakable Molecule. Before using it for garden mulch, I ferment the bale in a tub that has water, living dirt and compost tea. Haven't had any problems. This also seems to kill of latent mold spores.

Douglas—do you mean under water, like anaerobic fermentation? By which I mean, does it have to get stinky?

Mk Neal wrote:Douglas—do you mean under water, like anaerobic fermentation? By which I mean, does it have to get stinky?

That's how I do mine, nice and stinky. It's more neglect than high science but it's worked so far.

Especially with moldy bales I've been given -- after the better part of a week in the "pickling chamber" the mold never comes back, even when I water on top of it all summer.

In regards to The Unspeakable, I don't exactly know whether the soil denizens that break it down are aerobic. There's certainly enough traces of dirt in the bale to start things going. Maybe an aerated 24 hour soak would be more than enough.

EDIT: A bonus of thoroughly soaking is that I can cut the bale lengthwise in half or even thirds, using nothing but a long sharp serrated kitchen knife. It cuts as easy as cabbage. The shorter lengths are much handier to work with in the garden.