Natural film technique (NFT) hydroponic systems have been used since the '60s to successfully grow plants and herbs without the use of soil. This type of hydroponics system produces high-yielding plants and is relatively cheap to build. Although it can be very productive, this type of system is not recommended for the beginner green thumb. In an NFT system, the roots are suspended in the air with no buffer to protect them from over- or under-watering, so the plants can die quickly.
Cut a 4-inch-diameter PVC pipe to the desired length of your grow tube, using a hand saw. Use a net grow pot to trace the holes in the grow tube. Make the holes at least 6 inches apart to leave room for growth. Cut the holes out using an electric drill with a hole saw.
Apply PVC glue to the ends of the pipe and attach the end caps. Let the glue dry, then drill a 1/2-inch hole in the top of one end cap and the very bottom of the other, using a 1/2-inch hole saw. Attach two 1/2-inch elbows, both facing down, out of the holes in the end caps.
Determine where the water pump will sit when the system is running. Cut a 1/2-inch PVC pipe to the length needed to reach the 1/2-inch elbow on the top part of one end cap. Cut another length of 1/2-inch pipe to run from the pump to inside the plastic tote that will hold the nutrient solution. Cut one final section of the 1/2-inch pipe that will connect to the other 1/2-elbow and run into the top of the nutrient solution tote.
Cut the holes for the 1/2-inch PVC in the top and side of the nutrient solution tote using the 1/2-inch hole saw.
Set the 4-inch PVC grow tube so it's slightly slanted down toward the drain side, because the nutrient solution must continually run back down into the nutrient tote. Connect the PVC pipes to the water pump and into the tote. Also connect the drain pipe into the top of the tote.
Place an air stone into the nutrient tote and connect it to an air pump, using rubber tubing. Fill the nutrient tote with plain water and turn on the water pump. Make sure there are no leaks and the water flows up into the grow tube and back down into the nutrient tote.