Homemade Fly Spray for Horses: Recipes Worth Actually Trying

Three recipes keep turning up on livery yards, year after year: a diluted apple cider vinegar spray, a water-based spray cut with a few drops of essential oil plus something to emulsify it, and a cooled herbal infusion steeped from leaves like eucalyptus or lemongrass. Each one takes the edge off flies for a session or two. None of them are built to survive a hard sweat, a rain shower, or a full day out at grass, and none should go on without a bit of care in the mixing. Below are the actual proportions people use, the reasoning behind each, and exactly where the limits sit.

Why Riders Still Mix This Stuff Themselves

Every yard has that one person with a repurposed squash bottle of something pungent sitting on the tack room windowsill. The appeal is simple. It costs next to nothing to make, you control exactly what goes into it, and it's handy for a horse that's reacted badly to a shop-bought repellent before. It's also just what's on hand at nine at night when the midges are biting and the proper spray bottle is empty. None of that makes a homemade spray a replacement for a considered fly-control routine. It's a stopgap — a reasonable one, so long as you know what it can and can't do.

Apple Cider Vinegar Spray

Vinegar doesn't kill flies. It doesn't physically block them from landing either — there's no insecticidal action in it whatsoever. What it seems to do is make the coat smell and taste unappealing enough that flies drift over to the horse standing next to yours instead. Cold comfort if yours is the only one in the field. Genuinely useful in a full yard, though. Mix it roughly one part vinegar to one part water in a spray bottle — a cup of each is plenty for one horse — and mist it over the back, belly line, and legs, staying well clear of the eyes, muzzle, and any clipped or broken skin.

1. Combine equal parts apple cider vinegar and water in a clean spray bottle — about a cup of each is enough for one horse.
2. Shake well, then mist lightly over the neck, back, belly line, and legs, keeping clear of the face, sheath, or udder.
3. Reapply after hosing off, hacking out in the rain, or any session that leaves the horse properly sweaty.
4. Store it out of direct sun and give it a fresh shake before every use — it won't stay perfectly mixed on its own.

Diluting It Down for Grey or Pink-Skinned Horses

A grey with pink skin under a thin coat, or a horse fresh off the clippers, can find full-strength vinegar spray a lot sharper than intended. Cutting it to one part vinegar against three parts water makes a sensible starting point. Test it on a small patch of skin first regardless of coat colour.

The Essential Oil Spray

Citronella, eucalyptus, tea tree, and lavender are the oils that show up most often in home fly sprays, and the logic runs similar to vinegar — flies get put off by strong aromatics rather than harmed by them. Here's the complication: oil and water don't mix on their own, so a spray made from just oil and water separates within minutes, leaving concentrated droplets sitting on the surface instead of an even, diluted mist. A teaspoon of mild carrier oil, or a single drop of unscented liquid soap, acts as an emulsifier and holds the mixture together long enough to spray evenly. The same oils get a closer look in Citronella and tea tree for horses, including why concentration matters more than which oil you happen to grab.

1. Fill a spray bottle with around two cups of water.
2. Add ten to fifteen drops of citronella, eucalyptus, or tea tree oil — no more than that, however strong you want the effect.
3. Add a teaspoon of a mild carrier oil, such as sweet almond, or one drop of unscented dish soap to help it emulsify.
4. Shake it thoroughly right before every application, since the oil separates again within an hour or two.
5. Patch-test on a small area and wait a day before spraying it more widely.

The Herbal Infusion

An infusion is the gentlest option of the three, because it never touches neat essential oil at all — just the aromatic compounds released by steeping the plant material itself, at a fraction of the concentration you'd get from a bottled oil. It suits a horse that reacts to concentrated oils but still tolerates the vinegar spray fine, or one you'd rather not have smelling of vinegar all afternoon. The trade-off: no preservative in it whatsoever, so it lives in the fridge and gets used up within days rather than sitting on a shelf all summer. For more on the herbs themselves, Eucalyptus and lemongrass for horses covers what each one is actually doing in the mix.

1. Pour a couple of cups of near-boiling water over a large handful of dried eucalyptus or lemongrass in a heatproof jug.
2. Cover it and let it steep for about twenty minutes, much like brewing a strong pot of tea.
3. Strain through a fine sieve or muslin cloth until the liquid runs clear of leaf matter.
4. Let it cool completely before decanting into a spray bottle — warm liquid sealed in a bottle sours faster.
5. Keep it refrigerated and use within about a week, tossing it sooner if it starts to smell off.

Being Honest About What These Sprays Can't Do

None of the three recipes above are built to last. Sweat breaks them down within an hour or two of hard work. A shower of rain rinses them off completely. Even standing under a rug can rub a fair amount off before it's had time to do anything. The oil-based mixes separate in the bottle between uses too, so the dose you spray on Tuesday might be noticeably stronger or weaker than Friday's, depending on how thoroughly you shook it and how many drops actually landed in the bottle rather than on the worktop. That inconsistency is fine for a hack out or an evening in the school. It's not something to rely on for a horse standing out at grass for ten hours in fly season.

When a Spray Bottle Isn't Really Enough

A horse prone to sweet itch, one that lives out most of the day, or one heading to a show where reapplying every couple of hours just isn't practical — that horse needs more than a bottle mixed the night before. This isn't really an argument against homemade sprays. It's a reminder of the job they're actually suited to: a short-session top-up, not all-day cover.

Building Protection In at Bath Time Instead of Spraying It On

A spray sits on top of the coat, which is exactly why it washes and sweats off so fast. Work the same category of repellent oils into the coat during a proper bath instead, and they get carried down into the hair shaft and the surface of the skin, rather than sitting on the outside waiting to be rubbed or rained away. That's the thinking behind Repel Oil Shampoo — it puts the oils to work at the point where the horse is already being washed, rather than leaving a mist applied afterward to do the whole job alone.

Used the evening before a show, or after a muddy turnout has washed off whatever was on the coat that morning, Repel Oil Shampoo gives a clean, treated starting point. It doesn't rule out a top-up spray later if the flies are especially bad. The two aren't competing — one just lasts a great deal longer than the other.