Hydroponics is a method of growing plants without the use of soil. According to Dr. Merle Jensen of the Controlled Environment Agricultural Center at the University of Arizona, this means that plants receive their nutrition through solutions and are anchored in an artificial medium like sand, gravel or peat moss if necessary. This encompasses many possibilities for growing plants like carrots, which usually need soil for growth.
Mix two parts sand, one part perlite and one part peat moss to make your hydroponic potting mixture. Add water until the peat moss has absorbed the water.
Fill the plant pot loosely with potting mix and water it again until you see water drain out of the bottom. This will settle the mixture into the container.
Sow your carrot seeds into your plant pots by pushing them down 1/2 inch into the growing medium. Cover them over and tamp the surface gently. Make sure the mixture is warm, about 60 to 65 degrees Fahrenheit, or the carrot seeds will not germinate.
Mix 2 cups of a dry complete fertilizer in 1 gallon of water to make a concentrated nutrient solution. According to the Texas A&M Extension, dilute 2 tbsp. of nutrient solution in 1 gallon of water before using it on your carrots.
Water the planted carrot seeds every morning with warm diluted nutrient solution until it drains out the bottom. Save the drained water and use it again the following morning.
Place the container in a spot where it can get 12 hours of light, either sunlight or grow lights, each day. Keep the air temperature around it at 65 to 70 degrees Fahrenheit, or the flavor of the carrot will get too strong.
Harvest the carrots when their tops are about 1/2 inch wide, or smaller if you wish to grow baby carrots. Pull straight up to avoid snapping the root from the greens.