Shake any bugs from flowers and/or leaves, clean as needed
Sterilize a jar large enough to fit your nasturtium. Stuff with nasturtium flowers and/or leaves.
Pour vinegar over the nasturtium, cover the jar, and store in a cool, dark place.
Taste vinegar after a few days to see how it tastes. Continue to store if you want a stronger flavor. Some people let it infuse for up to a month.
When you are done infusing it, strain it through cheesecloth or a coffee filter into a new sterile jar. If using a cork, sterilize the cork by dipping it in boiling water a few times.
Store in a cool dark place (like a cabinet) for up to 3 months, or the fridge for 6-8 months.