Jerry Maren, a member of the Lollipop Guild from Il mago di Oz (1939), stood in for Margaret O'Brien in the scene where she is floating down the river in a bathtub.
The trailer for this film includes a specially shot scene of Margaret O'Brien visiting with Spencer Tracy. Tracy tells the child star he never wants to make a movie with her because she's too good for him.
The title is taken from The Holy Bible, The Song of Solomon, Chapter 2-15: "Take us the foxes, the little foxes, that spoil the vines: for our vines have tender grapes."
When Martinius and Bruna have gone over the revenue from the potato harvest, talk turns to the new barn and the needed lumber being controlled by the "WPB". Audiences at the time would know that meant the War Production Board. Established in January 1942, this agency of the federal government was tasked with converting the economy to war production and controlled vital materials and their distribution via rationing, ran scrap drives, controlled wages and prices, and more.
The role of Arnold was played by then very popular child star Jackie 'Butch' Jenkins. On the original one-sheets, "Butch" appeared in letters that were twice the size of the font used for the rest of his name and the names of the other supporting actors.