That is the farmers market that was located at Third Avenue North between Sixth and Seventh Streets.
It moved to Lyndale and Glenwood around 1937-38 where it still exists today.
They have the same style of shed at the Lyndale location. I don't know if they moved the old sheds or built new in the 1930s. There were 12 sheds originally but now they are down to three (it almost shut down in the 1970s).
There are also a lot of re-sellers of produce - not actual farmers selling their own goods.