By 2:30 a.m. most Sundays from April through Thanksgiving, a motley caravan of trucks, vans, and cars laden with everything including the kitchen sink lines up on Route 1A to secure a dealer space at the Todd Farm Flea Market in Rowley.

“Be Up Before the Cows!’’ is the slogan for the iconic outdoor marketplace in its 46th year.

Long before the sun rises, sellers stream onto the fields to unload and display as much merchandise as possible in spaces that are about 20 by 30 feet.

Some dealers are regulars who reserve and pay for a spot for the whole season. Others are first-timers who may have recently cleaned out a grandparent’s house and are looking to make some extra cash from family leftovers.

For the next several hours, flashlight beams bounce along fields damp with dew as dealers frantically unload and check out the competition at the same time. More than 300 dealers a week pay $40 apiece to sell on the two side-by-side fields until 2 p.m.

Ed Beattie, an antique dealer and auctioneer from Hampton Falls, N.H., is a weekly seller. He has been coming to Todd Farm since he was a teenager growing up in Rowley.

“I get set up around 3:30. It is busiest around 6 when the first batch of retail buyers come through and by 9 a.m., it has slowed down.’’

Beattie is there to buy as well as sell.

“If the day before was good for yard sales on the North Shore, then it will be a good day to buy at Todd’s,’’ he said.

At 5 a.m., the market opens to the public and thousands of treasure hunters pour onto the field in search of bargains, unique items, collectibles, vintage fashion, and antiques.

Peter Miller and his wife, Angel, of Danvers are regular shoppers at the sprawling outdoor market.

“We get there about 5:30 a.m. It is the thrill of finding something that gets us up at 4 a.m. and out the door,’’ said Peter. “I collect old advertising, architectural salvage — anything cool. If you are looking for something cool and different, Todd Farm is the place to go.’’

For those who just enjoy browsing, the fields offer a pleasant morning walking experience. Most Sundays there are plenty of parents pushing strollers, and dogs are always welcome. Many dealers leave out a bowl of water for thirsty dogs.

For hungry human shoppers there are snack bars.

The free parking is its own adventure. The lanes are little more than dusty cow paths. When negotiating the narrow trails, cars need to avoid branches, ruts, and pedestrians who are too busy looking at the unique items for sale to pay attention to traffic.

Weather impacts buyers and sellers. Even a threat of rain can discourage both, according to Beattie. Since there is little or no shade cover, attendance fades once the sun comes up and the temperature moves into the mid-80s.

Experienced shoppers know to wear a hat and bring water, but if need be there are always plenty of options for sale, from wide-brimmed sombreros to fedoras.

Todd Farm Flea Market, 275 - 283 Main St., Route 1A, Rowley; 978-948-3300/978-948-2217; www.toddsfarm.com.

Linda Greenstein can be reached at greensteinlm@gmail.com.