Pick the right part of a warm day
Bathing goes best in the warmest, stillest part of the day, once your horse has finished work and his muscles are already warm. A horse whose coat is warm from exercise rinses happily, but never pour cold water over one who is still blowing hard after fast work: walk him until his breathing settles, then start. Choose a wash area with firm, non-slip footing and decent drainage, because a wet horse shifting on slippery concrete is an accident waiting to happen. If there is a chilly wind despite the sunshine, pick a sheltered corner of the yard. A soaked coat in a breeze cools a horse far faster than most owners expect, even in the middle of summer.
Set up before you turn the hose on
Tie up with a quick-release knot or have a helper hold him, and put everything within reach first: a hose with an adjustable nozzle, a big sponge, a bucket of warm water if your horse dislikes cold water straight on his back, equine shampoo, a sweat scraper and a clean cooler. Start the water at the front legs so he feels the temperature and pressure somewhere unthreatening. Many horses who supposedly hate baths actually hate the surprise of cold water arriving on their back or face without warning, and a horse who has learned that the routine always begins at the legs rarely objects to the rest of it.
Wet, wash and rinse in sections
Work from the legs upward and from front to back. Soak one section at a time, sponge on the shampoo, and work it through the coat with your fingers or a soft brush so you lift dried sweat and stable dust out of the hair instead of polishing the surface. Concentrate on where sweat and grime collect: the saddle patch, the girth line, between the hind legs, around the dock, and down the backs of the legs where mud and sweat have dried together. Wash the head last, with a wrung-out sponge rather than the hose, and keep shampoo away from his eyes and ears. Then rinse for far longer than feels necessary. Dried soap left in the coat is the commonest cause of the itchy, scurfy skin that owners blame on bathing itself, so rinse until the water running off his belly is completely clear and the coat feels slightly squeaky under your palm.
Scrape, walk and dry him through
Strip the bulk of the water off with the sweat scraper, following the lie of the coat, then throw a wicking cooler over him if there is any breeze at all. Walk him in hand in the sun rather than turning him straight out, because a freshly bathed horse will roll in the field and undo your work in ten seconds; walking also keeps him warm while he dries. Before he goes back out or into any rug, check that he is dry through to the skin under the mane, behind the elbows and between the hind legs. Those sheltered, thicker patches stay damp long after the barrel feels dry to a quick hand.
A rinse usually beats a full bath
Reserve shampoo baths for shows, photographs or a genuinely filthy horse. Day to day in warm weather, a plain-water rinse after work removes the sweat that would otherwise dry itchy and salty in the coat, and it does so without stripping the natural oils that keep his skin supple. Save the full wash for the days when a rinse stops getting him clean. On KinsLe, putting the after-work rinse and the occasional full bath on the Care Teams list means whoever rides him knows the job belongs to them that day, and the finished wash is marked off where the whole yard can see it.