My horse has recently had a bout of laminitis and needs to be off all grass indefinitely. He is currently stalled until I can kill the grass in his run. He got the laminitis just eating the bits of grass growing up along the fence line, so I need to kill every last blade. The run is about 15 x 60 feet with an attached run-in. It is on a slope, mostly bare dirt, with a strip of gravel up the middle. The run-in is at the top on a level spot and there are issues with mud and standing water in that area when it rains. The horses have worn paths along the sides of the lot because the gravel hurts their feet. There is grass along the fence line on all sides and some growing up between the gravel. Fence is mostly three string elecrobraid. I board, so I’m not keen to spend thousands on completely replacing the footing to create a proper dry lot. The property owner has given me permission to kill the grass. He would probably let me put a layer of something (crushed gravel or similar) down as well. I was considering weed whacking everything down as low as possible and then spraying with vinegar on a sunny day, but I know that this needs to be repeated regularly. I’m also weighing physically blocking the grass under the fence with something like landscaping fabric, but not sure of the logistics of keeping it in place safely.
Does anyone have any ideas, suggestions, or experience?
I’m sorry to hear your boy has laminitis. Awful thing to deal with. 
Horses do a good job of killing grass. If you can, borrow a horse (with permission) and section the area in half or in quarters until the horse[s] have poached the topsoil and/or disrupted the growth. If that’s not an option, you can pull what you can and spray the rest, but there is a wait period and a safety component in doing so.
Are you certain that just nibbling grass is what contributed to the laminitis? Horses evolved to eat grass. If all the horses have the same farrier, and all the horses are wearing paths along the side because a little gravel hurts their feet, it could be mechanically (farrier) caused. Gravel shouldn’t hurt appropriately trimmed horses. Do you have photos of the feet?
Bringing in fill on a slope would be difficult and something requiring $$. In the short term, you can borrow or buy round pen panels and make a small medical paddock. But it may be time to consider a move and/or a change in farriers, especially if there’s any possibility this is caused by inappropriate trim.
When we remove lawns (I am in garden design) we basically scrape the soil containing the roots off with a shovel or scraper. It stops the grass regrowing from the roots. If you’re keen to spray something on, don’t bother with vinegar - just pour on boiling water. It kills weeds and is cheaper. Or even a steam cleaner if you have access to a large one.
Covering the area in a thick layer of mulch will help slow regrowth, but on a slope and with a hooved animal on it, that mulch is going to disappear fast.
I doubt that little bit of grass is what set off the laminitis.
I would assume its the way he is shod/trimmed, and his diet. Hay can put horses over the edge depending on sugar content faster than decent grass.
If you are removing the grass what @Xanthoria said works really well. I didn’t bother spraying anything.
I caught it early, thank goodness, so his symptoms were on the mild side and he has no rotation. He was never doing the saw horse stance or anything, just got reluctant to move and sensitive on the gravel. Late summer through winter he is a rock cruncher. He was getting free fecal water, foot sore and event lines last spring wearing a muzzle on full pasture. The symptoms all correlated to periods of grass growth after we had rain then sun. This spring I moved him into the dry(ish) lot, thinking the grass around the edge would not be enough to bother him, but alas. We have had the wettest spring in recent memory and not only was the grass going crazy, they were standing in fetlock deep mud for weeks on end. The vet agrees that it seems to be the grass, especially since the free fecal water has resolved since he has been off all grass the last two and a half weeks. His diet is otherwise low NSC (Timothy/Alfalfa pellets, TC Senior, Vermont Blend Pro, Omega-E). I haven’t tested the hay, but it is pretty dry, not especially rich orchard grass/timothy. He is 25 and has PPID (on Prascend). Not overweight and in light work 3 days a week up until the recent laminitis. Been barefoot his whole life and overall has good feet aside from some stretched lamina from the metabolic struggles the last couple of years. I attached a couple pictures from February. He is trimmed every 4 weeks and is never sore after a trim, but I did reach out to another trimmer just to get a second opinion. He will be in boots and pads for as long as he needs. Currently moving sound in his boots and wants to move.
I’m intrigued by the steam cleaner suggestion. Are you talking about something commercial grade or could I just order something off Amazon?
I’ve used a small handheld clothing steamer on weeds in the cracks on the driveway but it’s slow going. I have seen bigger weed steamers but I’ve always wanted to try a wallpaper steamer for this. Anyway, the bigger the better I’d imagine!
I use a butane torch. They also sell a monster torch called the Weed Dragon or something like that.
Are you soaking hay? It does seem pretty unlikely that a teeny bit of grass triggered this.
The problem with tiny bits of grass is that stressed grass is full of sugars. Those little nubs are torture if an animal is sensitive.
This seems to be what happened. I’m going to send the hay out for testing, but he is fine the rest of the year and on the mend since we pulled him off the grass and no other changes to his diet. The grass is the key variable.
I’m not sure if the property owner is going to trust me with a flame thrower lol
I hear what you’re saying, @trubandloki, but with untested hay - I’d be soaking the hay. Grass hay can be VERY high in sugars.
I am all for hay soaking too, if the need for less sugar is important.
Does your hay come from the same place? Do they rotate cuttings/what’s being fed?
I need to ask about the source(s). We had some obviously richer second cut over the winter that they gave each horse about two flakes a day in their stalls, but everything else is the drier stuff available free choice in slow feed nets 24/7. He didn’t have any trouble over the winter even with the additional second cut.
If you don’t bale your own hay, then it’s more than likely it’s coming from varying sources/fields. That alone can explain an issue. It also means that testing your hay is almost pointless, as the next batch will be different.
I think killing the grass is a good idea, but I would not put all my eggs in that basket.
You could put down woven or nonwoven landscape fabric. I used it in some of my turnouts to kill clover and it worked great. My horses ran over it and never had a problem.
I also have a master gardener friend who uses cardboard boxes to kill grass and you could even use that.
To pin either of them I used a hammer and strong metal pins:
They worked great in the fabric - not sure about cardboard but think it would work and I could check for you tonight when I got home.
And I’m so sorry to hear about the laminitis diagnosis.
I would love to use landscaping fabric but I don’t want to use the pins for safety reasons. I’m wondering if I could just weigh it down with bricks. My horse is very clever and will paw at things, so there’s a good chance he’ll just paw it out of the way to get at the grass underneath.
If it were me, with the barn owner’s permission, I would be employing a proper soil sterilant (pramitol or the like), with a 1.5 strength glyphosate added. Time it with the weather - one really HOT day to make everything dead and crispy, and then a good rain. Keep him inside for these two days to avoid ingestion.
The chances of your horse dying from the laminitis is far FAR higher than any complications from a vegetative control chemical.
