Not to sound like a broken record, but now's the time to gather mulch for the winter, it being the county fair season.

County fairs? These wonderful repositories of cotton candy, ferris wheels, canned tomatoes, hand-crafted quilts and carny barkers also boast a fair population of farm critters all concentrated in one place and all carefully bedded on great heaps of straw. Even better, some of the best hay around is being fed to the cows, sheep, goats and horses that will enter the show ring. Not all of this nitrogen-rich hay is eaten; a good deal of it ends up mixed with bedding. Handlers daily clean stalls, and huge piles of wonderful mulch quickly accumulate. So, for the price of entry, you can do more than pig out on barbecue sandwiches and get sick on roller coasters. You can also help the garden.

A few tips on gathering the best mulch:

* Get there before lunch. The earlier you go to pick up a load, the freer it will be of trash -- paper cups, bags, plastic spoons, cans, etc. Most herdsmen clean early in the morning, before 9, and the front-end loader usually doesn't get by until afternoon to remove piles of bedding into dumpsters.

* To save the price of admission, hit the fairgrounds the day after the fair -- again, early in the day. That's when crews come in to muck out the stalls. You might also be able to talk some nice front-end-loader operator into dropping a bucketful into the back of your pick-up truck, if you're fortunate enough to own one. One or two buckets from a front-end loader will just about fill a truck bed.

* If you're not lucky enough to own a pick-up, bring a box of three-ply trash bags. Lightweight bags can't take the weight of manure-rich straw and hay.

* Bring a pitchfork, which you should have anyway because it's a useful garden tool, and a rake.

* If you're after untouched bales of hay or straw, seek out the barn supervisor or someone in charge of a particular barn, and ask about taking home unused bales at the end of the fair. Do this late in the week, perhaps one or two days before the fair closes, when the barn supervisor will have some idea of what might be left over. You will, however, have to pay for unused bales of straw or hay. Straw is running about $1.50, and hay about $2 per bale, depending on quality and availability.

* If you're not ready for mulch just yet, but you plan on getting some later, touch base with the farmer who is supplying hay and straw to the county fair nearest you. Ask him about the availability of spoiled hay and possible delivery.

Here's a list of county fairs: MONTGOMERY COUNTY FAIR -- 16 Chestnut Street, Gaithersburg; I-270 to Montgomery Village exit, south on Route 355 to Chestnut. Closes this Saturday. Entry $3, parking $1. MARYLAND STATE FAIR -- Timonium; I-83 to exit 17; fairgrounds are just north of the Baltimore Beltway. August 28 to September 6. Entry $2. FREDERICKSBURG AGRICULTURAL FAIR -- Route 2, two miles south of Fredericksburg. September 2 to 11. Entry $3, parking $1. ANNE ARUNDEL COUNTY FAIR -- Sandy Point State Park, Maryland, off U.S. 50 at the Bay Bridge. Entry $2, parking, $1. CHARLES COUNTY FAIR -- three miles south of La Plata off U.S. 301; September 16 to 19. Entry $2. VIRGINIA STATE FAIR -- Richmond; Laburnum Avenue at Richmond-Henrico Turnpike; September 23 to October 3. I mention this one, even though it's far away, mainly because it will have one of the biggest livestock populations of any fair around -- about 6,000 head, which means that there'll be plenty of mulch.