No weed spooks a horse-hay customer like foxtail. "For your horse customers, how big of a deal is this stuff?" one grower asked the hay forums. "We have 5 horses and I definitely don't need to be vetting 5 horses due to mouth ulcers from hay." It's a fair worry — but foxtail is also one of the most misunderstood problems in the hayfield. The plant itself isn't toxic, cattle eat it happily, and cut at the right time it makes perfectly good forage. Everything hinges on one thing: whether the seedhead has gone hard.
This guide explains what foxtail is, why it wrecks horses' mouths but not cattle, the one timing move that solves most of the problem, and how to actually get it out of a hayfield for good — with university extension guidance and hard-won grower experience.
What foxtail is and why it shows up
The "foxtail" that plagues hayfields is a group of summer-annual grasses — yellow foxtail (Setaria pumila), green foxtail (Setaria viridis), and giant foxtail (Setaria faberi), named for their bristly, cylindrical seedheads that look like a fox's tail. They germinate as the soil warms, and they are opportunists: they explode into any gap in the canopy, especially the open, sunlit ground left right after first cutting.
That timing is the whole problem. Foxtail heads out fast and low, racing your desirable grass to set seed — and a shot of rain after first cutting sets off a fresh flush.
"One of the best deterrents for FT is to have a very thick stand of grass… And an abundance of moisture at any period of time after first cutting causes a flush of germination, compounding the situation."
— Vol, on HayTalk
Why it hurts horses — and why cattle don't care
Foxtail's danger is mechanical, not chemical. As the seedhead matures, each seed carries stiff, backward-barbed bristles (awns). When a horse chews mature foxtail hay, those awns work into the gums, cheeks, and lips and lodge there, driving painful ulcers, blisters, heavy salivation, loss of appetite, and — in bad cases — abscesses, with awns that can migrate deeper into tissue. Veterinary and extension sources agree horses are by far the most sensitive class of livestock to it.
Here is the part that changes everything, and it's confirmed by both the forums and the extension literature: foxtail is only a hazard once the seed is mature and hard. Cut it before that and it's just leafy grass.
"Cattle don't seem to be bothered by foxtail at all. It is the seed lodging between the tooth and the gum for horses that causes the inflammation. And it only does that if the seed is completely mature and hard. If you cut foxtail before the seed gets hard, there is no issue for horses eating it."
— Vol, on HayTalk
That's why experienced graziers are split on how much to panic. Growers who bale foxtail before it heads report feeding it for years with no complaints, while those who let it go to hard seed have genuine horrors to share:
"I baled it up and made a nice looking bale, was fairly leafy too. But seeds went everywhere… all the seeds are not good for the animals, get lodged in between the teeth and gums, can cause abscesses. I would cut it just before it started to head out."
— whitmerlegacyfarm, on HayTalk
Cattle, sheep, and goats eat foxtail readily and are rarely troubled by it — "they just slurp it up," as one grower said of his cows. So the same bale that's risky for a boarding barn can be fine winter feed for the cow herd. Know who your hay is going to.
The key move: cut before it heads out
Because only the mature seedhead is dangerous — and immature foxtail is decent, leafy forage — the single most effective thing you can do is time the cut to beat the seed. Take the hay just as the foxtail is about to head, and you get the tonnage without the barbs, and you knock back next year's seedbank at the same time.
"Taking second cut just before the foxtail heads prevents it from going to seed and regrowth was minimal. Since the foxtail was not headed it was still quite leafy and didn't seem to hurt the hay at all."
— FarmerCline, on HayTalk
The catch is the tight window. Foxtail typically heads out before your grass is "tall enough" for a normal second cutting, which is the exact bind so many hay growers describe: "It heads out before fields are tall enough for 2nd cutting." Two ways through it:
- Redefine "tall enough." Take a lighter, earlier second cut to catch the foxtail pre-head, even if the yield is modest. As one grower put it bluntly: "Best strategy is to redefine what's tall enough for second cutting. If you can't spray, mowing is your only weed control."
- Clip or shred it. If a patch isn't worth baling, run a flail or rotary mower over it right as it starts to head to stop the seed. Foxtail is stubborn and will try to re-head, so watch it and go again if needed.
One drying note: "When mowed, foxtail leaves can be slow to dry compared to the other grasses found mixed in," so give a foxtail-heavy cutting a little extra dry-down time and condition it well. For timing your cuttings around quality generally, our guide on when to cut alfalfa and hay covers the trade-offs.
Getting rid of it: stand, mowing, herbicides
Timing keeps foxtail out of the bale this year; these tactics shrink the problem over the long run. Foxtail is a grass, so the challenge is hitting it without killing your desirable grass — which rules out most broad grass herbicides and puts a premium on cultural control.
| Tactic | How and when | Notes |
|---|---|---|
| Thicken the stand | Fertility, pH, overseed thin spots; don't scalp or overgraze | The #1 deterrent — a dense canopy shades foxtail out |
| Mow / clip before seed | Cut or shred right as it starts to head | Your main tool if you can't spray; expect to repeat |
| Pendimethalin (Prowl H2O) | Pre-emergent — dormant early spring or between cuttings | Stops seeds germinating; won't harm established grass; blocks new seedings too |
| Quinclorac (Quinstar, Facet L) | Post-emergent — after first cutting on young foxtail | Controls emerged plants; follow the full label carefully |
A thick stand is where every experienced grower starts, because it's free and it works — a heavy canopy denies foxtail the light and open ground it needs. On the chemical side, the two workhorses do different jobs. Pendimethalin (Prowl H2O) is a pre-emergent that keeps foxtail seed from germinating; it's now labeled for established grass hayfields and, applied properly, won't hurt your existing grass. The trade-off is that it blocks any new grass seed, so don't use it in a field you plan to overseed. Quinclorac cleans up foxtail that has already come up, and growers who dial it in are impressed:
"I use Quinstar and literally have zero foxtail in fields that used to be a sea of it. Read the correct label (24 pages if I recall correctly) and read it carefully."
— VA Haymaker, on HayTalk
Selling hay that has some foxtail
If a little foxtail slips into a cutting, honesty is the best policy — and, it turns out, good business. Growers who disclose it consistently report that buyers trust them more, not less:
"I do declare the presence of foxtail. I had more people buy the bale versus those that did not. Not that big of a deal here."
— weatherman, on HayTalk
Sort your inventory by customer: send any hay with mature foxtail heads to cattle, sheep, or goat buyers, and reserve your clean, pre-head cuttings for the horse trade. Premium horse hay is where the margin is, and it's worth protecting all the way to delivery — a clean, bright, well-preserved bale is what earns repeat orders from picky barns. Storing it under tight, weatherproof bale net wrap keeps that clean hay bright and sheds water so it doesn't mold or bleach before it feeds out; for the horse-safety side of wrapping, see is net-wrapped hay safe for horses.
Frequently asked questions
Is foxtail hay safe for horses?
It's safe if it was cut before the seedheads matured and hardened. The danger is the mature seed's barbed awns lodging in the gums and causing mouth ulcers. Immature, pre-head foxtail is just leafy grass. Never feed horses hay full of hard, bristly foxtail heads.
Does foxtail hurt cattle?
Rarely. Cattle, sheep, and goats eat foxtail readily and are seldom bothered even by headed-out hay, because their mouths handle the awns far better than a horse's. Hay with mature foxtail that you'd keep away from horses usually makes acceptable cattle feed.
How do I get rid of foxtail in my hayfield?
Start with a thick, competitive stand — it's the best deterrent. Mow or clip before the seedheads form, and use grass-safe herbicides: pre-emergent pendimethalin (Prowl H2O) to stop germination, and quinclorac (Quinstar, Facet L) to control plants that emerge. Always follow the label.
When should I cut hay to avoid foxtail?
Cut just before the foxtail heads out. At that point it's still leafy and safe, going to seed is prevented, and regrowth is minimal. This often means taking an earlier, lighter second cutting than you normally would — cutting on time beats letting it seed.
Can I sell hay that has foxtail in it?
Yes — but disclose it, and match it to the right buyer. Hay with mature foxtail suits cattle, sheep, and goats. Growers who tell customers up front report it builds trust and doesn't cost sales. Keep pre-head, foxtail-free cuttings for horse customers.
The bottom line
Foxtail scares horse-hay buyers, but it's a timing problem more than a toxicity problem: the barbed, mature seedhead is what injures horses, and cutting before it heads out sidesteps the whole thing while still making leafy forage. Build a thick stand, mow or spray before it seeds, sort headed hay to the cow herd, and disclose it to your customers. Do that and foxtail goes from a deal-breaker to a manageable nuisance.
Protect the clean hay you worked for. XES Netting makes heavy-duty bale net wrap that wraps tight and sheds water, so your premium, foxtail-free horse hay stays bright and sound from the field to the barn. Shop net wrap →
Sources: The Horse, "The Dangers of Foxtail in Your Horse's Hay" (accessed July 30, 2026); Virginia Cooperative Extension, "Control of Common Grassy Weeds in Pastures and Hayfields" (SPES-58, accessed July 30, 2026); Ohio State University Extension, OSU BEEF Team, "On the Prowl for Foxtail Solutions" (accessed July 30, 2026). Grower quotes from HayTalk.com discussion threads, linked above.
Image: "Setaria pumila" (yellow foxtail) by Krzysztof Ziarnek, Kenraiz, licensed CC BY-SA 4.0, via Wikimedia Commons.
