Intro to Hydroponics

Written by Sophia Anner, ESLLC 2016-2017

As part of my Community Engagement project with the Food and Garden section of the Center for Sustainability, I have become very interested and focused on hydroponic farming. Hydroponics uses water completely in place of soil that is found in traditional farming. At the Center, we had two hydroponic towers running over fall quarter and into break, and though they are now stopped, we have some grand plans for our hydroponics in the future, which I’ll explain later. First, let me explain the parts that go into a hydroponic tower.


All towers will have a reservoir. In the towers that we had, the reservoir was incorporated as the bottom of the tower, and it has a pump inside that carries water to all the plant receptacles on the tower. A different version looks like long, horizontal panels with six to eight plant receptacles in each. Many of these panels can be hung together, one on top of the other, and they can all be connected to an irrigation system that pumps from a bucket full of water.

The seeds are grown in what we call seed starts, that is done in a material called Rockwool. Rockwool is spun fibers of molten chalk and basalt rock that is compressed into a sheet of seed starts with little holes for the seed to go into. First quarter, we grew basil and swiss chard. A member of our team, Zane, cared for the seed starts until a stem began to grow. At this point, the sheet is broken into its smaller squares and the plant in the Rockwool is placed into the plant receptacles.

In terms of day to day care, the pump is on a timer so that it is running 15 minutes every hour for 24 hours. There are also lights that provide the insolation needed for photosynthesis surrounding the tower. These are on a timer to be one from 6 am to 6 pm. Another possibility would be to move the hydroponic tower outside without lights and let sunlight do the work. Every few days, we fill a five-gallon bucket with water and add two nutrients to it that act as a fertilizer for the plants. It is essential to check the water level at least every two days because if the pump tries to run while there is no water, it will permanently break. We also test the pH and add either pH up or pH down (two different chemicals) to make sure the pH is between 5.5 and 6.5. Hydroponics actually tend to grow better because the nutrients go straight to the plant roots, instead of being fed in through the soil.

At the end of break, our swiss chard didn’t make it, but we had a very successful basil growth, most of which was donated to Nagel Hall, and they used it in their meals! This ties into the major plans for hydroponics towers. It was given to me as an initiative to consider possibilities for hydroponics on campus, and through working with the rest of my team, we came up with some very exciting ideas:

  • Grow edible foods on hydroponic towers for the dining halls to use
  • Grow edible foods on hydroponics to donate to our campus food pantry
  • Establish a hydroponic tower in a local elementary classroom, teach the students how to take care of it, and teach some short lessons on the importance of fresh food
The result of our basil hydroponic tower at the end of break.

We’re still in the works of figuring out which of these we’re going to do because we’ve hit some barriers. If we want to grow for dining halls, we would need to figure out what food safety regulations we need to be able to follow (I’m not quite sure how we got the basil to Nagel), determine what Sodexo would want from us, and be able to grow the amount that they would need. The food pantry is looking like our best option, but it is also just getting started. In addition, most people don’t know about it. A grad student, Alfredo, is developing the food pantry for students who can’t pay for groceries on their own or need some support in addition to dining hall food. The plan is to have a website with the available food that you can “shop” for online, and then pick it up at a specific location, which might end up being the old center in JMAC. It would be incredible to grow for the pantry, but we would have to still follow food safety regulations, and it is also unclear what kind of demand we would even have. The final option, growing for a school, is a large project that would take a while to establish, but it would be very rewarding. I’ve already talked to one professor about this, as she has a connection to a local Montessori school that would be able to integrate this project into their curriculum well.

Clearly I have a lot of ideas, but like Chad said at the sustainability retreat, we don’t want to reinvent the wheel. I have plans to meet with two girls who were studying abroad and had previous ideas about hydroponics at DU. It also makes sense to consider what other people and schools are doing. Cornell University has a professor that established a high school program related to aquaponics. Aquaponics is the combination of aquaculture (raising fish) and hydroponics. The fish provide nutrients to the plants and the plants clean the water for the fish. Many universities have school farms that contribute to the dining halls or a local food pantry, but not many of them use hydroponics. The best example is six Georgia Tech engineering student who developed a common space with glass walls to act as a greenhouse, hydroponics systems surrounding it, and an aquaponics system in the center. Not only does this provide produce to the local food bank, the school’s farming market, and the dining halls, but it provides a common space for students to hang out and learn about hydroponics. Hopefully, something similar can be incorporated into DU sometime in the future!


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