The Waltham Farmers Market launched its 22d season this weekend, and will run every Saturday from 9:30 a.m. to 2:30 p.m. through Nov. 10 in the Sovereign Bank parking lot at Moody and Main streets. In addition to the more than 30 vendors selling produce, eggs, cheese, meat, and handmade items, the market will feature eight free one-hour concerts through the season. Steve Taddeo and His Swing Senders will launch the series at 11 a.m. Saturday. For a complete lineup of vendors and concerts, visit www.walthamfarmersmarket.org. Debit and credit cards are accepted, as are WIC coupons and EBT cards by some farmers; seniors get a 10 percent discount from some vendors.