Find out when blackberries are in season in your area. Blackberries ripen faster in warmer climates. In the United States, blackberries in the South ripen around May and June. In the North, they ripen around July and August. Ripe fruit should be firm with shiny black skin. You don't want to pick unripe berries because they won't ripen once picked.
Take walks by riverbanks and near creeks looking for wild blackberries. Bring your basket and look for ripe blackberries to pick. Make sure you stick to nature trails or public parks for safety. It's not a good idea to pick wild blackberries from roadsides or from around crops because they may have been sprayed with pesticides or belong to the person who owns the land.
Find out if your area hosts a wild blackberry festival. Many states and counties host festivals where local growers and farmers can sell their blackberries, and it can be a great place to stock up. Festivals also provide a variety of foods made with blackberries and possibly bake-offs and other special events.
Find your nearest pick-it-yourself wild blackberry patch. This can be a fun activity for the family and you can be assured that the blackberries, though still considered wild, are cultivated and not covered in pesticides.
Visit your local farmer's market. You can find wild blackberries for sale from local growers and those with blackberry patches on their land at different times during the summer, depending on your location.