DIY hydrophonic herb garden

My previous blog post might have been a bit hard to grasp, so let's move on to a bit easier topic: gardening. Gardening is fun and rewarding, but Finnish summer isn't very warm or long. A few days ago it was snowing, which isn't very fun at this time of the year.

To get most out of the short summer I decided to build a hydrophonic garden. Last summer half of our plants didn't grow too well because it was too hot on the balcony (it has glass windows so the whole balcony is essentially a greenhouse) and the plants didn't get enough water and nutrients. Since we are going to anyway garden lots of stuff on the balcony during this summer too, hydrophonic garden was a nice and simple DIY project which could make the growing process easier.

Hydrophonics has numerous advantages over traditional soil growing methods. To name a few:

  1. Faster growth
  2. No weeds, less pests/diseases
  3. Consumes less water
  4. It's easy

There are multiple different ways to build a hydrophonic watering system. I chose to build a drip system, which is simple and relatively easy to build. Below is a schematic of the system.



  • Pot/tray combo from local grocery store, 20 €
  • Water pumping related stuff from Finnish aquarium shop
  • water (actually waste) bucket, about 8 €
  • herbs about 10 €
  • clay pellets about 15 €



Total sum is about 120 euros. This means that my DIY system is cheaper and bigger than most of the ready-to-go systems which you can buy from stores. It could be cheaper, but I had a few design constraints:

  • the system must look good (no random stuff floating around the balcony)
  • easy to maintain

This means that all of the components except air pump must be hidden. At first I tried to put the air pump inside the pot but after first test run I took it out, because it was too risky to keep it so close to the water.



I had to make a small hole to the bottom of the tray. It's a bit smaller than the diameter of the overflow pipe to keep the pipe in place without any additional support. I did add some duct tape to the other side to be sure it stays put, but it's not necessary.



The 15 litre reservoir sits at the bottom of the tray. The pump and air stone are submerged there.
The actual drip pipe is attached to the pump which pumps the water up to the herbs. If you're building similar system make sure that you buy powerful enough pump. Cheap ones can't lift the water high enough.



There's a T-piece at the end of the drip pipe to get the pipe cover whole growing area nicely. I made some holes to pipe so that the water can flow freely to the growing tray.



There has to be some kind of filter at the bottom of the tray so that the clay pellets don't block the overflow pipe. For that I harvested some metal mesh from old tea ball infuser and placed some rocks on it. After that I filled the tray with the clay pellets which I had flushed with water earlier.




I did also small cleft to the side of the growing tray to get the water pipe, air pipe and pump cord out of the pot. Duct tape is there to keep them in place. However, I'll have to get some sticks to keep the drip pipe in desired position. Now it's just hanging over the herbs.



The system has been running now a couple of days and the herbs are already growing new leaves (except for the basil which didn't like the cold weather, but it's still alive). There's some nutrient in the water to keep them happy. I'll have to monitor the system to see how often I have to refill it, but I believe the refill interval will be 3-4 weeks. Those big sticks at the corners of the pot are there just to support a gauze. It's on the pot during nights to prevent the herbs from dying because of the cold weather.