The word sow has two completely different meanings:

1. To plant seeds in the ground. When farmers sow wheat in their fields, they scatter or place seeds in soil so they'll grow into crops. Gardeners sow vegetable seeds in spring, and by summer they're harvesting tomatoes and carrots. You might hear someone say “you reap what you sow,” meaning the results you get depend on the effort you put in, just like a harvest depends on the seeds you planted.
2. A female pig, especially one that has had piglets. Farmers raise sows to produce more pigs. A male pig is called a boar, young pigs are piglets, and a female pig is a sow. This word rhymes with “cow,” while the planting meaning rhymes with “go.” On a farm, you might see a sow nursing her piglets or rooting around in the mud.