For the past few months most of the world has been in quarantine and you may think that this is the new normal, especially now that “re-opening” has been rolled back or paused in many places.
I live in Texas and our Governor said it was a mistake to start opening so quickly and has since issued close orders for many social places. With that being said I thought it would be a good time to blog about a project I’ve been working on. We have a lot of white tail deer in my area and as a result it’s more difficult to grow food. Sure I can hide those tasty crops behind rosemary bushes but you can only have so much rosemary in a garden. Let’s talk about sustainability.
For many years now I’ve dreamt of starting a commercial farm with either hydroponics or aquaponics and I’ve setup a few small hydroponic systems but never tried my hand at aquaponics. One thing that was clear to me in February when everything shutdown and no one could find toilet paper is that we all need to be more self-sufficient; so, I adapted a koi pond that I established in November as a test bed for my first aquaponic system.
What is aquaponics?
Aquaponics simply put is the process of growing veggies in water (without soil) and feeding your crops with the waste from your fish. You can use a variety of fish such as tilapia, walleye, or koi. Many commercial farms use tilapia because they can sell the fish as well. In my case, I chose to use koi because they are colorful and make great pets as they live for more than 30 years. Certain types of koi can also sell for thousands of dollars. The following picture is of a few of my koi. Pictured clockwise from the top left are Goldie (goldfish), Frank (koi), Cowboy (koi), and Flight School (butterfly koi).
Aquaponics can be quite a bit less expensive that hydroponics because you feed your fish, not your plants and organic fish food is much cheaper than organic hydroponic plant food.
Sustainability with Aquaponics
The basics of aquaponics or hydroponics are that the plants need to harvest their nutrients from the water, which means that they will need to have their roots grow down into the water so they can absorb.
With my setup I have to pump the water upwards and then use gravity to cycle the water back into the main koi tank.
I was afraid that the water may sit for too long if it was trickling in on one side and out the other so I decided to use 3D printed bell siphons, which is a great system that uses physics to empty water.
3D printed bell siphon:
The following is a look from inside the plant rails. Water is pumped from the koi tank into the rail at the top right behind the bell siphon in the picture below. As the rail fills with water it will spill over the snorkel of the bell siphon which will trigger the siphon effect and drain all the water from the rail. This continues over and over to keep the water fresh:
Below is an animated depiction of how a bell siphon works:
Learn more about bell siphons and aquaponics here
What’s needed?
The list is really small. All you need is a medium for the plants, some type of pvc railing (I used 5” fence posts), net pots, bell siphons, fish in a tank, and a pump with filter to clean the tank and pump the water. It’s also worth noting that Beaver Plastics makes lettuce rafts which is what you see in commercial farming. They float on top of the water and in this scenario would be a bad solutions as the koi would have no sunlight and they’d also eat the plant roots.
I also have a rain water tank to capture water because it’s much healthier than the tap water in my city. Koi can only live in a certain PH range and it’s important to monitor your water’s PH or the plants and koi can both die. One advantage to hydroponics is that plants generally like more acidic (PH < 7) water and koi do best with a PH between 7 and 8.6. This is where tech comes in. You can use an Arduino board and PH sensors to measure the water and send the data to Azure IoT hub. How cool is that? More on Azure in a moment.
After a few weeks of growth you can see how cool aquaponics is!
That’s right, you see heads of lettuce among other plants like basil and curry. I’m so excited.
Bringing it back to data
For many years now you have been hearing about “the internet of things” or IoT for short and for most of us this technology is not something we deal with from day to day. You may think of IoT data streaming from a remote oil well or from medical monitoring equipment; but, not generally household items even though your refrigerator could have IoT capabilities such as auto ordering food when something is low.
In the case of farming, as mentioned above, you need a way to monitor the PH levels in your pond. This goes for an aquaponic garden or a koi pond. As a technologist I look for ways to use technology to make life easier for myself and those around me. Using the PH sensors from Arduino is one such way I can do this. Think about setting up an IoT device to read PH levels of a single or multiple tanks/ponds and then using an Azure app service or PowerBI report that I could access on my phone to get warnings so I can care for my plants and fish better with less work. I think this is truly what technology is about.
For more on IoT I recommend checking out the IoT developer resources on Microsoft here:
https://developer.microsoft.com/en-us/windows/iot/
I don’t have an Arduino but it’s in the mail and once it arrives and I get everything setup I’ll post a follow up. Stay tuned. For now stay safe, healthy, and curious.