Hay & Forage Grower, Jan 1, 2001

White keeps hay coolest, company study shows. Henry Ford used to say of his Model T that customers could have any color they wanted, as long as it was black.

For years, that was pretty much the case with hay tarps: black was basic. And dark-skinned covers protected hay from rain very well. But hay directly beneath black tarps was being "super-dried" to virtually zero moisture content.

"Until about 15 years ago, we used black hay tarps," says Glenn Knopp, president of Inland Tarp & Liner at Moses Lake, WA, a major manufacturer of hay covers.

"Then I noticed that the top bales in a tarp-covered stack were consistently lighter weight. We had a stack of 100-lb bales - stacked nine high - and bales in the top two layers weighed 15 lbs less when we loaded out, compared with when the bales went into the stack.

"Even if all the moisture was being dried out of the hay, bales shouldn't be losing that much weight," Knopp adds. "Something else was happening to the hay."

As Knopp studied the problem, he found that the heat was actually breaking down the chemical composition of the hay. Heat absorbed by black tarps and transmitted to the hay beneath was literally cooking the nutrients out of the forage.

"So we converted to a metallic-silver tarp, and that helped the situation considerably," he says. "But heat was still affecting hay quality."

Hay grower Bill Miller was noticing some differences, too.

"I didn't make any formal comparisons of different-colored tarps, but I have noticed that condensation is worse on the hay side of dark tarps," says Miller, of Sage, AR.

He speculates that the condensate is being drawn from the hay underneath.

Knopp made a side-by-side comparison of three tarps in California's Imperial Valley on a sunny day when the air temperature was 85. He placed thermometers under the tarps at the ends of bale stacks.

"Under the black tarp, the reading was 125," he says. "Under silver, the thermometer read 112. Under the white tarp, the temperature stayed within a degree or two of the outside air temperature."

That was more than three years ago. Shortly afterward, Inland Tarp & Liner began making hay tarps that are white on one side, silver on the other.

"We put a rain gutter on the white side, although the tarps are reversible," he says. "We encourage customers to use the white side up, but I think some producers still put silver on the outside because of habit."

Knopp notes that producers in areas with heavy snowfall also like to cover hay with the silver side up so snow will melt quicker.

"For another thing, when you're tarping a bale stack on a bright, sunny day, the white surface has a glare that is hard on the eyes," points out Miller, who admits he often turns the silver side up for that reason.

"My theory is, you don't want to add any more heat than absolutely necessary," Knopp says. "After you stack bales, they go through a heating process anyway, which can raise the temperature 10 or more. If you add another 10-20 to the stack by wrapping it in a dark-colored tarp, you're increasing the chance of a breakdown in the hay's nutrients."

In Knopp's opinion, that makes white the best color for hay covers, although silver is still the standard for the industry. But, then, it took a number of years before the Model T came in colors other than black.

"If you don't have a shed to store hay in, tarping may be the next-best option.It may even be preferable - both economically and for loading ease, say growers. Don't protect your hay and you'll probably lose 12-20% to water damage. If you're baling $100/ton hay, that's $12/ton or more lost."

"Covering hay definitely pays," says John Starr of Covertech Fabricating, Inc., a hay tarp manufacturer in Toronto, Ontario. "We find a grower can save an average 20% of his hay, compared with leaving bales outside."

"Hay that has been protected sells better, too," says Glen Knopp, president of Inland Tarp & Liner, Inc., Almira, WA. "We typically see buyers paying $5 to $10/ton premiums for hay stored under cover."

When Rollie Bernth, of Ward Rugh Hay Co., Ellensburg, WA, buys hay, he sends a crew out to tarp it right away.The company buys hay from Columbia River basin growers and exports it to the Far East - primarily to Japan.

"Not many farmers we buy hay from have hay sheds," says Bernth. "A lot of them grow alfalfa on leased land and do not want to invest in a permanent structure."

His company stockpiles tarped hay on the farms until it's hauled to Tacoma or Seattle for shipment overseas.

"When you're shipping hay 6,000 miles, you want to be handling quality hay," says Bernth. "And, while a hay tarp may not be as good as an enclosed shed, it's definitely better than no protection at all."

But tarps must be in good condition to be effective.

"Tarps are subject to wind damage in severe winter weather, and a tarp with a hole or rip in it can be worse than no cover at all," says Bernth.

Economically, tarps may be a better investment than sheds. Knopp estimates the cost of a reinforced hay tarp this way: A nine-bale high, four-bale wide, 54'-long stack of 100-lb rectangular bales holds 65 tons of hay. At $80/ton, that's $5,200.

"Uncovered hay will lose 11% to spoilage, mostly in the top layer," Knopp says. "That's $572 worth of hay. The cost of a 25 x 54' Super Tarp, rope and stakes totals $384. That's a savings the first year of $188 over the cost of the tarp."

The tarp should last three years or longer, which puts the savings for three years at $1,332.

"Tarped stacks are easier to load out of than a hay shed, too," says Conway Miller, Melbourne, AR. Miller and his son, Bill, grow grass and mixed grass-legume hay they sell and feed on their own farm. "Trucks can pull on either side of the stack and load out in less time than from a shed."

The Millers have used hay tarps for the past seven years in a region that gets 40" of annual precipitation.

"We're not losing much hay - maybe 2%," says Bill. "We take care of the tarps and get four or five years' use out of one. When a tarp finally gets a hole, we still use it as ground cover under the haystack."

"We have a good horse-hay market for Bermuda grass, and horse owners like bright, fresh hay," he adds. "Many times, a buyer will buy the hay stack, tarp and all."

That prompted the Millers to become tarp dealers a couple of years ago.

"We've even sold tarps to lumberyards to cover dry lumber," says Conway Miller.

The Millers stack big round bales in a 3-2-1-pyramid fashion. They use a 25 x 54' tarp to cover 66 bales, each 4 x 5'.

"That size tarp will cover 72 bales, but we tarp fewer bales in a stack and pull the tarp over the ends of the bales," says Miller. "The tarp costs $310 and covers 33 tons of hay - for a cost of less than $10/ton. Over a four-year life of a tarp, the cost is just over $2/ton of hay covered. We figure it's profitable not only to tarp our better-quality hay, but common fescue hay as well."