Prepare the jar by cleaning and drying a medium-large mason jar thoroughly.

Slice carrots and cucumbers into matchsticks and layer them tightly in the jar with the radish.

In a medium saucepan, combine equal parts water and vinegar, and bring to a boil. Stir in garlic, salt, oregano, and sugar, and simmer for 5 minutes.

Remove the brine from heat and allow it to cool for 5-10 minutes before pouring over the veggies in the jar.

Cap the jar tightly and let it sit at room temperature for 10 minutes before transferring to the refrigerator for at least a few hours before enjoying.