In a TikTok video, @amongthejungle says to put old carrot tops in a pan and fill it with water, covering the tops halfway. The carrots should grow roots in a few days.
Next, dig holes in your garden deep enough to cover the carrots up to their stems. Once planted, pat the soil so they're nice and snug and sufficiently water them.
A good rule of thumb is to give the plants an inch of water every week while the roots are maturing, then increase your carrots’ watering to 2 inches every week.