Over there beside the highway, past the waiting army of empty tractor trailers, under the long open sheds, is a sight for hungry eyes -- more watermelons than a reasonably stable mind can imagine.

There are rows of watermelons. Pyramids of watermelons. Mountains of melons. Small cordilleras of them. Jillions of watermelons.

There are Crimson Sweets (round with squiggly stripes), Jubilees (long with squiggly stripes), Charleston Grays (long gray-greens) and Sugar Babies (small and dark green).

Well, summertime is nothing without a watermelon and watermelon is nothing without a Laurel. Before you can spit out another seed, Laurel's watermelons will be soothing palates in New York, sweetening life in Toronto, making Cleveland tolerable and yes, let's say it, probably drawing flies in Philadelphia.

An explanation is in order.

Watermelons, plainly, don't come from the back room of a neighborhood grocery. They come from farms and it just so happens that the fields of Delaware and Maryland's Eastern Shore are among the country's more prolific sources of watermelons.

Laurel, being more or less in the middle of this fruited plain, is one of the country's centers for the shipment of watermelons and canteloupes, through the Southern Delaware Truck Growers Association, a farmers' cooperative that operates the auction on the edge of town.

In the big melon picture, dominated by the likes of Georgia, Texas, Florida and South Carolina, Delaware and Maryland are not titans, but they contribute their share. Maryland raised 2,700 acres and Delaware 1,900 acres of watermelons in 1979, according to the Department of Agriculture.

Much of that produce moves through the Laurel auction. By the time the lazy, hazy days are gone, around 2 million watermelons and 800,000 canteloupes will have been sold at the Laurel market, where buyers from throughout the Northeast have been camped since mid-July to bid on the loads of fruit the farmers bring in each day.

On a good day, and almost every day has been good this year, the farmers' trucks stretch in a double line for blocks, inching up slowly toward the auction block where the slick boys from the city try to outfox each other with their bids and still turn a profit.

They're slick, all right, but the farmers have their number in a way. John Trice, a farmer from Hurlock, Md., had just sold a truckload of his prize Crimson Sweets the other day and he paused to explain.

"You'll notice all the small pickup trucks here," he said. "That's because the melons on a small truck will bring about 10 cents more apiece than melons on a big truck. They look prettier. The buyer can get closer to them. You try to move as much of your crop as you can on a pickup.

"But the bidding here is real serious and there is some cutthroat bidding on the block. The nice thing about this market is that anyone, a big farmer or a little one, can come here and sell and be competitive."

Obviously, a farmer has to do everything he can to get a price. Trice raises about 20 acres of watermelons (enough, he noted, to feed a small town) on his big farm and trucks the ripe fruit to the market every day, using a small vehicle whenever he can.

The trouble is that the 1981 watermelon is selling for about 3 cents a pound and the crop is extraordinarily abundant. Last year, the same watermelon sold for 8 to 9 cents. With that kind of price, everybody and his brother planted melons this year and, wham, there went the prices.

Last week, as evening temperatures were falling all along the coast, melons were selling for just 2 cents a pound here, and David B. Horton, manager of the auction, was on the edge of despondency.

"Nobody wants to eat watermelons when it's cool," he said. "And if the weather doesn't change soon, we can write this year off. Just have to try again next year. As long as the supermarkets keep their prices up, we're not going to move many melons."

The 40- to 45-pound melon that Trice could sell here last year for $5.10 goes for between $1.50 and $2 this year. But the 2-cent or 3-cent pound of melon Trice sells here was going for as much as 15 cents in Washington-area supermarkets last week, indicating somebody's doing well with watermelons, if not John Trice.

"It's hard work, with the cultivation, the irrigation, the picking and grading by hand," Trice said, "but I've been doing it year after year -- 20 years now -- and my father did it before me. I'd say it is a pasttime, to pick up a few extra dollars."

As Trice talked, a beige Lincoln Continental rolled up and the buyer inside asked about more melons. Trice had no more and the car moved away. "I believe that's your story," the farmer said. "I'm driving an old Ford."