Sunday should have been opening day for flea market season in Massachusetts.

Giant flea markets in Seekonk, Grafton and Rowley were supposed to be open April 5 for the first time this year, each with hundreds of vendors selling everything from apple-peelers to zinc pennies.

But like everything else in Massachusetts and across the country, flea market season is on hold.

The massive Brimfield Flea Market in south central Massachusetts has already canceled its May 12 opening; the Somerville Flea Market on Davis Square canceled a pre-season sale scheduled for last weekend; and the year-round Raynham Flea Market closed its doors March 8 with no way to know when it will reopen.

Mike Peters, a co-owner of the Grafton Flea Market, said Sunday was supposed to kick off the market's 51st year of business.

"We're just ready to go," he told WGBH News. "The place is spic and span. We got all the tables ready. We just need the people."

Peters said the hundreds of vendors who rent spaces from him are going to take a terrible financial hit. "There is no compensation for the dealers that are missing out on four or five weeks of income," he said. In addition, he has a dozen employees — like parking attendants and concessions managers — who are going unpaid. Peters is hoping the $2 trillion federal rescue bill Congress passed last week will offer some support for him and his employees. "You know, we've got to take care of them, too," Peters said.

The long-term impact will depend on how long people have to stay in their homes, he added.

"It's going to be tough," Peters said. "I mean, we use all the capital we have, but we we have to find these creative ways to get income to stay afloat. If it's three or four months, we don't know. So, I mean, that's the main concern is just trying to stay afloat. You know, and it's not just us. It's ... it's every place."

There are more than 1000 flea markets nationwide with more than 2 million vendors and annual sales of somewhere around $30-$50 billion, according the the National Flea Market Association.

The Massachusetts markets are small businesses with a handful of employees, but they are also serve as storefronts for hundreds of independent vendors who now have nowhere to sell their wares.

"Much like any other small business, we're going to see what type of federal relief we can get," said Christine Kelly general manager of the Raynham Flea Market. "But you have to understand, we're in a different position because we're also supporting the livelihoods of hundreds if not thousands of people that set up here every week. This is how they support their families."

Many of her vendors have full time jobs, but the Sunday market "is their supplemental income," Kelly said. With coronavirus shutting everything down, "they could very well be out of work at their full time job. And this is what they were hoping would get them through. And they can't even do that now."

Kelly said that she fears even when the statewide stay-home advisory is lifted, there will still be restrictions on large gathering into the summer, which could continue to impact flea markets for months.

But Tim Anderson, the volunteer president of the flea market association, said markets may have an advantage when businesses are allowed to reopen. Outdoor flea markets often have more space than an indoor mall or big-box store. "I think that helps us," because it is easier for shoppers to maintain distance from others, he said.

Anderson also thinks markets nationwide may see a spike in customers when they reopen, much as the industry saw enormous increases during the economic crisis of 2008. After the economic turmoil of the shutdown, "people are going to be looking to get stuff cheap," Anderson said, and "you can buy jeans for pennies on the dollar at your local flea market."