While the brown PCB angle and the Samla box is not exactly winning any beauty contest I'm very satisfied functionality wise. The Samla box serves as a second stage for the young plants after they grew to big for the breeding box, after that they will get their dedicated pots.
The 3D printed clamp was nicely adapting from a pottery pot to a plastic box without any adjustments to the design. It holds very tight and is able to support the 70cm long metal rods just fine.
I added the clamping mechanism of the first clamp design to the top of rods to give them more support, otherwise it was very easy to jiggle a rod around with your hands due to the long length of the rods, now they are sitting firmly in place. I will design an additonal minimal clamp similar to the one for #MoAgriS: Modular Agriculture System to give support for long rods like these. I think the design should scale well to 1.5m and longer.
The plants are enjoying the light so far. For the estehtics I think having a proper PCB with probably white soldermask (or none and just have tinned copper for an all metal look) will go a long way to improve the looks. I think an all metal surface finish could give the setup a very nice industrial kind of look. Though for the plastic parts I would stick with white or for the clamp maybe go with the color your plant pots are in. I ordered some terracotta spray paint and see how that works in conjunction with my terracotta pots.