Last week I got to try Cornell hydroponically grown lettuce at the dining hall, then go to a presentation and discussion by Ph.D. student Erica Hernandez and undergraduate Christopher Levine on hydroponics, primarily related to growing lettuce. Going into the talk, I had only a very rudimentary understanding of hydroponics. When I thought of hydroponics, I basically thought of plants growing directly in water with no soil. This is true to some extent, but as I learned from the talk, there are actually multiple hydroponic systems with varying degrees of complexity. The simplest of these which we learned about was Deep Water Culture. This system was the most similar to what I thought of when I considered hydroponics, as the plant roots sit directly in the water. The most complex system was aeroponics, in which the plants actually hang in the air!
I found it interesting that all of these systems had positives and negatives. What is constant among all of these systems, however, is that three main things must be supplied: oxygen, nutrients, and water. For instance, deep water culture requires a large amount of water and hence a vast amount of space. A pump system supplies the nutrients and oxygen. Aeroponics requires less ground space, and the plant roots are already in the air, hence obtaining a large amount of oxygen. The misting in this case supplies the water and nutrients. One more thing I found particularly interesting was that if a plant is hydroponically grown, that does not mean it is organic. This is due to the fact that the nutrients generally come from mined minerals, which then go through a process to be purified into just the essential nutrients the plants need, and nothing more.