Hydroponics 101.3: The Circulation Method

Hydroponics-101

Picking up where we left off in our Hydroponics series… The circulation method of hydroponics is ideal for you if you have a few more dollars to spend (as compared to the more limited Kratky Method) and you would like your students to make a hydroponic system in the classroom. It is a great way to integrate the engineering design process and STEM into your curriculum as well as offer authentic learning to your class. It also offers you a way of integrating principles of chemistry and physics into your curriculum.


 

We’re currently in a series exploring Hydroponics and Aquaponics.
{Read the previous entries here Hydroponics 101.1 and Hydroponics 101.2}


 

In the circulation method, you need to provide a nutrient trough for the plants to bathe their roots in. This can be done in many ways. Two methods that I have worked with are a floating bed system and a rail system. With both systems I had great success.

Circulation-Method1

With the floating bed system, have your students construct a sturdy box of 2×4 lumber about two feet wide and four feet long. Attach a piece of plywood on the bottom and drill a hole for a bulkhead attachment to allow water to drain from the bed to a reservoir below the bed. Next, place a rubber pond liner inside the box and cut a small hole in the liner to match up with the hole you drilled earlier. Screw down the bulkhead and tighten it so that water will not leak out of the box. Now cut 2 inch holes into a piece of ½ inch thick pink Styrofoam insulation board. I used a 2 inch circular hole saw in a drill bit and ran the drill BACKWARDS so that the Styrofoam was not shredded.

Circulation-Method2

Now you are ready to fill the reservoir with water. I use a large plastic container (about 25 gallons) with a small aquaponics pump on the bottom and a hose running up to my growing bed. I fill the reservoir with water, add my nutrient solution, turn on the pump and circulate the water. Monitor the water height in the bed so that when you add your plant cups their roots are touching the water. I also would recommend you add a PVC pipe below by attaching it to the bulkhead with a PVC fitting so that water flows back to the reservoir.

Next we’ll explore light requirements, planting and monitoring your system.

Friday Follies: It’s All Fun and Games Until….

Saturday morning. Spending some time challenging a couple hundred kids with fabricating foam rockets. They are loving getting out of the classroom and into the cafeteria for a hands on experience building foam rockets and then launching them. They persistently brainstorm ways to get the rockets to go farther and higher. Through trial and error, mistakes and occasional failures, they achieve success! Rockets are flying everywhere. Bouncing off walls and garbage cans, other kids and the occasional unwary instructor who happens by. The curiosity, creativity and risk the kids take with the engineering design process are inspiring. If through this activity we can connect to real life applications and get them into Maker Spaces and Maker Labs, it will all be worth it. Worth the drive to the city early this morning to set up. Worth the exposure to all the kid germs and sticky hands grabbing hot glue guns from my helpful hands. Worth the parents hogging the supplies because they are as excited as the kids to engage in novel learning. And definitely worth the experience of having these wild ones use me as a target to aim the rockets at. “What if we hit Miss Sue? Do we get a prize?” No. No, you don’t. Rockets

Yes, it’s me, Sue Brainiac. The Head Brainiac Jerry’s long suffering wife. Brainiac Jerry loves offering events for poor underprivileged inner city kids that have never had the opportunity to torture Mrs. Brainiac with their attempts at foam rocket building. Yes, I understand that offering STEM activities encourages collaboration among students and sparks excitement about learning that may lead to a little girl becoming an engineer or a boy realizing he COULD go to college and do fun stuff for a living. It’s novel learning at its best. Developing synapses in the brain through presenting challenges to solve. Showing kids that tenacity and grit and hard work can actually be fun and rewarding. Blah blah blah. Okay. Kids learn to love science and math and make it applicable to everyday life. How nice for them.

But on a lovely Saturday morning , Mrs. Brainiac could be enjoying coffee on the deck and instead she is supervising kids from ages five to, well, whatever age the oldest parent is. Using scissors and hot glue and rubber bands. All her favorite things for kids to play with. And now the finished rockets are bouncing off her in spite of the oath to “not aim at anything living” that we made them take prior to launch.

How about we go back to the traditional education experience? Worksheets. Lectures. Videos of other people making things. Kids love watching other people have fun in videos. Tests! What about tests? Those take up lots of time and keep kids busy. And why aren’t these kids playing video games? That would keep them out of Mrs. Brainiac’s hair.

The worst part is all the questions they have. What if we use an extra rubber band? What if we angle it? How about if we make the fins longer? Shorter? More fins? Less fins? I have no idea! I’m not a scientist! But I am smart enough to let them figure it out themselves by trying it. And then when they figure it out and tell me, I smile knowingly as though I knew the answer all along and say, “There, now aren’t you glad you figured that out by yourself without me telling you the answer?”

Augh, the kids found me hiding behind the waste baskets writing this blog on my Ipad. “We want to make rockets, we want to make rockets.” Well, when do I get to make one of these rockets? I’m sure I can find a way to hit that top window they are all aiming for.