Cut the top from one soda bottle, then remove the black base from another bottle. (Do this by filling the bottle with hot water to soften the glue, then prying the base loose.)

Invert the base and cut a hole in it for your seedling or cutting, and another one to insert aquarium tubing.

Insert aquarium tubing through the hole and connect the other end to your pump.

Gently insert a seedling or cutting through the center hole in the inverted base and wrap aluminum foil, dark plastic, or paper around the setup to exclude light from the roots and discourage algae growth.

Try to keep the nutrient solution pH between 5.8 and 6.5 and the temperature at about 70 F, and change it every two weeks or so. Some people suggest using a half-strength solution for the first week.