Constructing Our Hydroponic System:
Bob and I decided that we wanted to make our system as simple as possible for several reasons. (1) This is our first time experimenting with hydroponic plants and we didn’t want to get too in over our heads (2) By keeping things simple, hopefully we can influence others who do not have gardening or hydroponic expertise to give it a try (3) Most of our materials are recycled materials and because of that, we not only keep cost down, but we find other uses for things like the coffee container that may otherwise be thrown away.
Here is what we have been working on the past week and a half:
Here Bob is cutting a hole in the top of the coffee container. The smaller hole is for the PVC pipe which will create that suction we need to force water up the tube and into our growing medium. The larger hole is for the yogurt container, which is where our plant and growing medium will sit. We were careful not to make the holes too big because we want a good seal for maximum suction. We also don’t want light reaching our nutrient solution to avoid algae build up.
Bob is using a 3/16” drill bit to drill holes into the yogurt container. There are cups called “net cups” available online and in local hydroponic stores, but we want to make our design as cost efficient as possible, so we chose to emulate the net cups. The idea is that the holes in the cup allow for our nutrient solution to reach the plant, but also so that he roots of the plant have somewhere to go once the plant grows in size.
Here is the PVC pipe inserted in the coffee container with a small tube connecting it to the inside of the yogurt container. This design works on the idea that air will be pumped down the tube from the capped end of the PVC. This air will reach the bottom of the tube housed in the PVC that will create a suction (assuming we have a good seal on the PVC cap and where the tube enters the cap) and this suction will force our nutrient solution up the PVC and will travel from the PVC to our yogurt container by means of the small piece of tube shown in the center of the picture. This system is a drip system.
We have been having a lot of trouble getting a nice, steady, even drip from our system. We tried all sorts of different sizes to cut the PVC, we adjusted the tube depth, and even tried different angles for the PVC, however, the drips were inconsistent and we didn’t like what we were seeing. Last class we were fortunate enough to have a hydroponics expert, Marc from Hydro-Ponics of Harrisburg, come in to give us some pointers on how to effectively grow plants in hydroponic systems. He proposed that we get rid of the PVC pipe entirely. Our system works on the principle that the solution is oxygenated by the air pump and is then pumped up a tube housed in the PVC that will travel to the yogurt container to give our plant the nutrients it needs. This is a fairly simple system, but he recommended we get rid of the PVC pipe and make it even simpler.
Our new design features a shorter length of tube running from the air pump into the coffee container. This tube will rest at the bottom of the coffee container with an air stone attached to it to oxygenate the solution. So we nixed the PVC, used less tubing, and essentially we have the same basic function that our previous design had, just with less material. The purpose of the PVC contraption was to deliver the oxygenated solution to the plant. However, our new system works a little differently in HOW it delivers the oxygenated water to the plant. Instead of a drip system, this is now what is commonly called a “deep water system” where the plant is actually submerged in the solution.
Unfortunately we only have one coffee container, which meant we only have one lid. I did what any Tech Ed. major, or what any perfectly rational human being would do, and I used duct tape to patch up the hole where the PVC used to be inserted. We also dilled more holes in our yogurt cup because Marc advised it so that we are sure that our plant receives ample nutrients and has somewhere to stretch its roots our when it comes time for that. We also drilled a hole using the same 3/16″ bit we used earlier in the bottom of the coffee container for the air hose to feed into from the air pump. We inserted the tube and then applied a cheap silicon adhesive to it to ensure that we do not have any leakage. because the tubing is bigger than 3/16″ but smaller than 1/4,” we just wiggled the 3/16″ bit around a little bit in a circular motion until we got our desired hole size in the container.
We’re ready to plant now. We just need to mix the nutrient solution, decide on what seeds we want to plant, and track down an air stone.