One warm summer evening, a large group of horse enthusiasts gathered for a private polo match in Upperville. The expansive, deep green polo field was lush and well manicured. The horses were strong, swift and meticulously groomed.

In the next field, Tom Davenport of Hollin Farms was harvesting and baling a beautiful field of orchard grass hay. He paused and casually scanned the polo match, then noticed something that disturbed him. Surrounding the polo field were acres and acres of pasture that had not been grazed or cut. The grass had gone to seed.

"No attention had been paid to the pastures that could have fed all those polo ponies," Davenport said. "I suppose that people just thought they could buy hay from Pennsylvania and New York at the feed store like people buy bread and beer at the supermarket. They can, but it will be more and more expensive."

As the horse population in Loudoun, Fauquier and surrounding counties grows, local haymaking is not keeping up with demand. Not enough landowners are producing hay specifically designed for equine consumption, so horse owners must go elsewhere to get it, often at higher costs. Much of the hay that feeds the tens of thousands of horses in Northern Virginia is imported from as far away as Canada, Michigan, Wisconsin and Ohio, even though this region has always been considered prime land for hay production.

The problem? A mix of basic economics, shrinking farmland and lack of farmers with the expertise and skills to make top-quality hay.

The equine hay shortage isn't readily discernable. Large, round bales, weighing 1,200 to 1,400 pounds, can be seen in fields throughout the area this time of year. But most of those bales are made from fescue, a nonnative grass that is most commonly used for cattle feed, landscaping and compost mulch. Gary Hornbaker, rural resources coordinator for Loudoun's economic development office, said round bales typically sell for about $25 each, although bales that are covered or stored inside can bring $75 to $80.

Top-quality equine hay typically consists of orchard grass, timothy, alfalfa or other nutritious species, or a combination. It is commonly produced in small, square bales that weigh 20 pounds to no more than 80 pounds each and sell for $5 to $6 and up.

Although some local owners feed their horses fescue, many avoid it. Local hay farmers say that fescue, especially when produced in July and August, can be bitter and tough. A bigger concern is that it can contain the endophyte fungus, a naturally occurring infection that benefits fescue but can cause reproductive problems in pregnant mares, including late-term miscarriages, lack of milk production and thickened placentas that can be difficult for foals to break through, especially if born in fields without human help.

Making quality hay takes skill, patience and good weather. Taking into account the delicate digestive system of horses, equine hay must be grown properly and cut in a timely fashion. Quality equine hay is cut when the grass is immature, cured under hot, dry, sunny skies and baled when the moisture content is no more than 15 percent. To prevent rot and mold development, fresh bales must be picked up and stored immediately. Feeding moldy hay to horses is dangerous, sometimes deadly.

Equine hay that has been properly produced is virtually weed free. Break open a bale and the grass feels dry inside -- not particularly hot or ever damp to the touch -- and it has a snappy, crunchy quality when crushed between the hands. High-quality hay is fragrant, smelling of sun-dried grass, not of straw. Bales containing too much moisture are often unusually green. Moldy hay smells sour and musty.

Labor costs and the expertise needed to produce quality equine hay cause some farmers and landowners to avoid the venture altogether. Hornbaker said one farmer can easily make round bales on 250 to 300 acres. Because it takes more manpower to make square bales, one farmer can handle only about 100 acres of that kind of hay.

Still, farmers such as Davenport eagerly seek out land to farm. As in Fauquier and Prince William counties, Hornbaker's Loudoun department teams up with the Virginia Cooperative Extension office to work with landowners and farmers to select, grow and market profitable crops, including hay.

"It all comes back to quality," Hornbaker said. "If you've got a $50,000 horse, you want good feed."

Robin Hirst of Fox's Wink Farm in Orlean agrees. Her efforts to find a farmer who can convert her acreage to hayfields have proved unsuccessful, but she feels fortunate to have found a local hay source. She bought 622 bales of Hollin Farms orchard grass hay this year (now priced at $2.95 to $5.95 a bale, depending on content) to feed her six horses. Last year, she paid $10 a bale for similar hay from Canada.

"It's lovely that the price is so much lower, but [local hay] also doesn't have to move between two or three middle people, and the horses absolutely adore the orchard grass," Hirst said. A Virginia native, she remembers her grandfather fretting about weather and haymaking on his farm at the corner of what is now the Beltway and Route 236.

Hirst said she likes knowing where the hay she buys was produced and prefers to support the local economy rather than importing feed from outside the state. She said she thinks homegrown hay has nutrients and values not found elsewhere, offering unique benefits, "just like local honey." After living away from the area for many years, Hirst was surprised when she moved back to Fauquier and couldn't find local hay.

"Fescue was rampant. It was a hassle for farmers to put up hay, and they didn't feel the need to bother," Hirst said, adding that the price per bale isn't the only cost consideration. Her horses leave inferior hay on the ground, wasting it.

"At $10 a [Canadian] bale, you feel like they're eating caviar, so you don't want to waste any of it. But if it's not edible, they're going to trash it," she said. "On the other hand, if it's high in nutrients, they won't need as much and will eat less."

For Davenport, haymaking is a family tradition. His father, Robert, who died in 2002 at 96, started Hollin Farms in Delaplane in the early 1950s. Davenport's son, Matt, 32, earned a master's degree in environmental engineering from Cornell University and has taken over most of the responsibility for the farming operation, which includes raising natural Angus beef and producing organic and other hay.

For Tom Davenport, farming is a societal as well as economic issue. He is critical of a region that is rapidly becoming what he calls a "county of lawnmowers," people who move to the area say they like the pastoral look but don't want to work the land. Despite Northern Virginia's high demand for quality equine hay, too many landowners are holding property as a real estate investment rather than viewing the land as an agricultural venture, he said.

"This is some of the best pastureland on the East Coast," Davenport said. "Just mowing it or bush-hogging it seems like a big waste when an animal could enjoy the grass. Doing something with the land has a public use and private benefits. Instead of mowing, pay farmers to farm the land."

At Tom Davenport's Hollin Farms in Delaplane, above, Raul Napoles bales hay while Matt Davenport picks up the bales. For Tom Davenport, below, haymaking is a family tradition. "The horses absolutely adore the orchard grass" from Hollin Farms, said a horse owner.