In ancient Latvia, Zalu Diena ("day of grasses") was a festival held on June 20. The women and girls gathered grasses and flowers to weave into wreathes. Farmers cut birch boughs and put them in their barns; this prevented mice and other rodents from eating the harvest. John's Grass was given to the cows and sand was sifted onto their heads; this caused the cows to have sweet milk. Young girls gave crowns of flowers to their potential suitors; both children then wore their wreaths to bed and, if they dreamed of each other, they were a match.