Creating a soda syrup garden in outdoor plant boxes is a fun and flavorful way to grow your own ingredients for homemade sodas. The best plants for this purpose are those with strong, aromatic flavors that can infuse syrups with refreshing tastes. Here are the top choices:

1. Mint – A classic for sodas, mint varieties like spearmint and peppermint add a cool, crisp flavor.

2. Basil – Sweet or lemon basil brings a unique herbal twist to homemade sodas.

3. Lavender – Its floral notes create a soothing, aromatic syrup perfect for craft sodas.

4. Lemongrass – Adds a citrusy, tangy kick to syrups for a tropical touch.

5. Rosemary – A bold herb that pairs well with fruity or citrus-based sodas.

These plants thrive in outdoor plant boxes with well-draining soil and plenty of sunlight. Harvest leaves and stems regularly to encourage growth and use them fresh or dried for syrup-making. Experiment with combinations to craft your signature soda flavors!