Prepare a boiling water bath canner and 3 pint jars.
Wash, trim, and chop the vegetables you're using (go for similar sizes so that everything pickles at the same rate).
Combine the vinegar, water, and salt in a large saucepan. Set it over high heat and bring it to a boil.
Once the brine is boiling, add all the chopped vegetables. Cook just until the brine returns to a boil and then remove the pot from the heat.
Pull the jars out of the canner. Divide the garlic cloves, mustard seeds, and red pepper flakes between the jars.
Using a slotted spoon, fill the jars with the chopped vegetables, leaving 1/2 inch headspace.
Fill the jars with brine, taking care to retain the proper headspace.
Tap the jars gently on the countertop to loosen air bubbles. Use a wooden or plastic chopstick to remove any stubborn ones.
Wipe the rims, apply the lids and rings, and process the pickles in a boiling water bath canner for 10 minutes.
When time is up, remove jars from the canner and set on a folded kitchen towel to cool.
Sealed jars can be stored in a cool, dark place for up to a year. Any unsealed jars should be refrigerated and used promptly.
I like to give this pickle at least a week of rest before I crack open a jar.