My hydroponic project

I have always been curious about growing plants/food with nothing more than water and some nutrition. After reading an article about it in a science magazine I decided that it’s time to build my own hydroponics system to see if it actually works :). With a little greenhouse out in the backyard (that no one uses) it’s even more compelling.

Once some initial research on the internet was done I decided that I’ll go with a Nutrient Film Technique (NFT) design that uses PVC pipes. This seemed like a good way to start since it’s straightforward and doesn’t involve any complicated parts (well so I thought, but more later). After a bit more research I bought the materials (recycled PVC pipes, wood, a pump, etc) and the tools to build the system. First off were the pipes… cutting them into size and making the inlets for the plants later on was actually quite easy once the proper markings had been made. That was my first time to work with PVC and I was surprised how well it handles with the jigsaw and the other tools. Once the pipes were ready I started working on the stands that would allow to hang the pipes. I figured that by hanging the pipes I would have better control later on the slope and setup of the system.

Once the PVC pipes were in place in the greenhouse I could start working on the piping to and from the PVC pipes. For that I bought some smaller irrigation and gray water pipes. Since the PVC pipes had different heights I built in a little reservoir on top that allows to distribute the pumped water evenly over the two pipes. The thing to say here is that this only works because I got a pump that is quite strong and can push the water 2 meters up.
After finishing all the work I finally could test if the whole water cycle worked. Turning it on for the first time showed that there were still a couple of leaks that needed some attention but other than that it was ok.

In parallel to building the system I grew a couple of seedlings in rockwool so they would be ready once I got everything up and running. Actually putting them into the small plastic baskets and then into the PVC pipe felt like the system was finally complete. The last thing to do was setting the timer and let it run and wait (and change the water every week). That was a couple weeks/months ago and today I finally can enjoy  the fruits (or vegetables) of my work.

Looking back, kind of like a review, the issues I discovered with my system are the following:

  • The round PVC pipes don’t allow for the regular plant baskets since they are flat at the bottom and thus all the water just flows underneath them without touching them. That is a problem as long as the plants don’t have any long roots that could touch the water. By heating (or melting) the baskets I deformed them so they have the shape of the PVC pipe at the bottom and thus are in the water stream. I don’t like this approach since, it takes a lot of time to deform them, it makes the baskets usable only in the round PVC pipes and it’s not as stable once the plants grow bigger.
  • The openings in the PVC pipes are too large… that allows light through to the roots which is not all that good. So far I was lucky and there hasn’t been that much of a problem with that, but I’m sure it would be better if the roots were in a darker environment.
  • The piping that goes from / to the water reservoir… this is just a PITA to set up and seems to be a point where weaknesses can occur. My issues were that the drainage pipe couldn’t handle the amount of water at first. Using a bigger pipe solved the problem but I still think it’s not ideal. I already got a NFT design in mind that would not have any or almost none feeding and drainage pipes…
  • The water storage container is too large in area, e.g. 10 liters barely cover the bottom where a taller and narrower container would have a higher water level with the same amount of water, thus the pump would always be submerged.
  • Having Perlite loosely in the PVC pipe (without the baskets) doesn’t work that well since it’s moving slowly downwards every time the water gets fed through. Watching it is quite funny since it’s almost like a little avalanche that is coming down.
  • Once the plants get bigger the baskets tend to tip over since they don’t have any weight and no hold with the big opening in the PVC pipe.

Huff… seems like a lot of issues there :). Well I guess it was a really good learning experience. Anyway, the salad and vegetables are tasty.. that’s what counts in the end.