Layer carrots, peppers, onions and oregano in wide-mouth jars. Press them down so they are packed tight.
Pour over brine. Leave about an inch of space at the top of the jar.
I drop in pickle pebbles to weight the veggies down. The weight is optional cut the veggies should stay under the brine. The weight makes sure this happens.
Cover the jars. Use airlock lids or fermentation lids designed for wide mouth jars. Airlock lids will reduce the fermentation smell in your kitchen. If you leave the tops on tight, you should burp them daily to release the pressure.
Ferment at room temperature for a minimum of 7-10 days. Taste the brine to make sure you like the flavor. I like mine a little more ferment-y, so I leave them fermenting closer to 3 weeks.
When the carrots are the flavor that you like, seal them with a tight lid and store in the refrigerator.