Second iteration of the HydroTree.

There were some points in the V1.0 that I wanted to address in the second iteration.

  1. The noise of the air pump. It needs to go down.
  2. Grow top is too thick for the apple tree to grow roots nicely.

Addressing the problems in the design.

To address the noise now got a new different type of air pump. Tetra APS 50 air pump. It too promises to be extra silent. Before starting I did try it out and it seems to be quite the bit more silent then the JBL air pump.
To make the grow top thiner so that the roots have easy access to the the nutrient solution I used only one layer of the 20mm thick foam. It will float like a raft on the nutrient solution and giving instant access to the rock-wool cube for the nutrient solution. Now that the grow top is thin I still need to work the air pump and electronic junction box somewhere. After some thinking I decided that they need to go under. See picture πŸ™‚
I can then also add some insulation to further dampen the noise of the air pump.

Some shopping done πŸ™‚

Parts list :

  • Black pot decorated with some straw
  • Insulation foam. 20mm thick.
  • Plastic electric junktion box
  • Some Wago connectors
  • Tetra APS 50 Air pump
  • Silicon tube for air hose
  • Air stone of any kind
  • Safety valve that allows only air flow one way and nothing in.
  • Submerged water pump
  • Decorative stones
  • 20mm wide and 1mm thick white plastic sheet
  • 5mm plexi glass
  • Elastic glue
  • Hot glue gun plus hot glue.

That is quite some items but it is all you need.

Let the work begin πŸ™‚

I started by using the pot as a modelΒ and drawing the circles on the insulation foam. Five in total. Four sides and a bottom. In the plan there was only four in total but I think a bit more space will not hurt.

Then it is the trusty Jigsaw and cut out all circles.

Four of the circles need to be hollow to for the sides. Just free-handing with the felt pen to mark down where to cut from. Cutting is quite easy as if you just gently press the jigsaw in full RPM into the foam it will go through it and you can start from inside of the circle. Four circles later and one of the them needs a 1cm bit carved out so I can run electric cable through it.

Glue, glue, glue, glue and some clamps create a nice cake πŸ™‚

Holes to the pot

Next while the base cake is drying I start working with the pot.
Two holes needed at the bottom to accommodate the water pumps electricity cable and the air hose.

Sealing the holes

I used a lot of elastic glue. The one I have is quite strong and I put a good chink on both sides.
Using an emergency valve for the air hose so in case the air pump shuts down for some reason, no water comes through the air hose.
Now here is my first mistake. Without thinking it through I drilled the holes. Too close to the sides and it would place the air hose and electricity cable right under the side of the base cake. Shit.
Well need to carve some bits out to accommodate the clumsy positioning of the holes.
Next time I will place the holes further from the sides but not too much. Don't want them in the middle of the pot either. Then they would need to make a odd curve due to the air pump and stuff that is places in the base cake.
Put a 20cm piece of hose on the water pump to make it really circulate the water.

Sanding to shape

Now that the base cake is dry enough, I wanted to sand it to be uniform shape. Set the belt sander to 90degree angle Β to make sure all looks nice and even.

Safety first

Remember to use safety glasses and mask. Never forget that the dust from that thing is quite toxic. Well I got no idea how toxic but I'm sure it is not healthy πŸ™‚

Touch of paint

Finished the sanded base cake with a coat of black paint I had on shelve. I put a thick layer so it would also even the cake out a bit. Just a FYI it doesn't it dries to a thin coat and still shows all imperfections. Another mistake πŸ™‚ Well next time I'll add a filler all around to make it look nicer.

Ok time to let everything adhere and dry πŸ™‚

Day 2

I came to my workshop and next up was checking out how the glue has hardened around the electric cable and air hose at the bottom of the pot. Filled the pot up with water checking after each 5 litres that it is not leaking. It seems to hold exactly 20 litres and thats full. No leaks and left the thing bubble at the other end of the work-desk.

Grow top is up next. In Version 1 I had the whole of the air-pump and electric junction box in it and the top was whopping 10cm thick creating the problem that how would I get the water to the roots before they actually reach the solution themselves. Now in this new one I use only one foam disk that is 20mm thick. Hole in the middle to have the rock-wool where the tree will grow from.
It is the first part of the video. You see me sanding and fitting πŸ™‚ Good idea to fit it more often then not as if you over-sand it you need to start over. Fits nicely and floats on top of the nutrition solution.
I had the idea for the decorative stones. Plan is to build a top disk from 5mm plexiglass and make some sort of low sides to it so the stones could be nicely housed on it and it would be easy to take off and put back on again in case needed.
Sand and fit the disk. Drill a hole in the middle where the tree will come through. Then use hot-glue to glue 20mm white plastic strip to the side and center.
Nicely the rookieness of my video making skills show up here too as I am glueing the sides in and my iPhone runs out of battery πŸ™‚
Sucks but here is a picture of the end result.

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  1. Philippe


    Hello Jussi hope you are well I am quite interested and impressed by your work and wanted to further discuss it with you in particular in relation with the food computer pls drop me an email best philippe

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