Rockwool is the most popular medium choice and is both sterile and porous. If you go with rockwool, be careful to keep it from becoming too saturated. This can lead to root suffocation, stem rot, and root rot. Grow rock is another popular option that has a neutral pH and holds moisture well. This medium is reusable if cleaned thoroughly, which can be beneficial for growing hydroponically in your home, but might be tedious on a larger scale. [4] X Research source
Do not use a metal container as your nutrient reservoir. Metals can corrode or oxidize, releasing chemicals that can disrupt the supply of nutrients to your plant. [5] X Research source
Some lettuce types are more sensitive to nitrogen that others, so make sure that the nutrients that you purchase are for the right kind of lettuce.
Purchase both up and down pH adjusters that, when added to your reservoir, will be able to bring the pH back to the correct level. [14] X Research source
