I designed this vertical hydroponic planter from scratch. It's still in early stages but I think most of the bugs have been removed. It allows for as many layers as you like. I have 5 layers on mine, allowing for 25 plants.

I mounted the tower into the lid of a 9 litre 'very useful storage box'. In the bottom of the box is an aquarium pump. That pump sends water to the top of the tower via a 13mm ID (18mm OD) section of tubing. The water then gets spread to the outside walls (internally) and it trickles down through each of the pods back into the tower and eventually back down to the box.

The oversized thread on the base section is quite tight and may need a bit of cleaning up. But once it fits it's very satisfying to play with.

Some adhesive is required. The water dispenser needs to be stuck to the inside of the cap. I thought about redesigning it as one piece but removing supports may have been a little tricky. Also the splash dampener should be glued to the inside of the base. This is an optional piece but was put in to try and reduce the sound of water returning to the box (it's similar to aquarium noise but may make some people want to pee all the time)

All extra parts I have used are listed below (no affiliate links so I'm not trying to make any money).

I have some plants beginning to grow from seed. I tried a synthetic foam grow media but I think a rockwool or something similar would have been better. With small seeds be careful with the positioning in the cups as they can easily be washed into the bottom.

One small observation is that there is very minor seepage of water through the PLA layers. It may be worth tweaking the print settings to push more filament. Or give the outer cups a layer of varnish or something. However, I did find that the hydroponic growth formula tends to crystalize and blocks a lot of the gaps so it's not like there are puddles everywhere.

https://www.amazon.co.uk/dp/B0146PSD9O?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1 https://www.amazon.co.uk/dp/B0BYMSMM94?ref=ppx_yo2ov_dt_b_fed_asin_title https://www.amazon.co.uk/dp/B08GJXLXHZ?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1 https://www.amazon.co.uk/dp/B09QGN9XBQ?ref=ppx_yo2ov_dt_b_fed_asin_title https://www.amazon.co.uk/dp/B01ENC6T2I?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1

I've also designed a mount to sit on top of the tower and hold some grow lamps to support the growth of the seeds. This is optional but it is designed to work with this:

https://www.amazon.co.uk/dp/B0B1LJ33GN?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1 https://www.amazon.co.uk/dp/B09C88G6ST?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1 (A basic level of wiring is required to attach a plug but you may be able to but E27 lamp holders pre-wired.)