When you grow hydroponic plants under grow lights space is very precious so optimising it becomes important. The issue I had last year was I had one plant per large bucket so having 8 plants under my 400W grow light was a pain and left little space for other soil plants.
I had seen previously hydroponic cloner devices which were expensive as pre made units and even still quite expensive using all the right parts for a DIY build. I took this idea and used cheap parts to make something similar which would allow me to grow many small seedlings still in a hydroponic medium ready to transfer later to larger net-pots.
This is what I came up with:
1 small plastic container from bunnings $7.95
I bought 30 small lettuce grow pots from trademe for $10
Rock-wool I already had but this is also cheap from SOG
While the rock-wool soaked in water for 5 minutes I simply drilled holes slightly smaller then the diameter of the top of the lettuce pots into the lid of the plastic container, take your time here and go easy with the pressure here so you do not break or crack the lid. I then removed the bottoms of the lettuce pots as I did not want the roots from the plants to get stuck in it. I then took my soil based seedlings and washed them off in a bucket of water to carefully remove as much of the soil as I could before cutting a small slit into the rock-wool and inserting the seedling into it with the roots exposed at the bottom. I then slid the rock-wool into the lettuce cups which was snug enough to hold it in place. I drilled two small holes for 4mm air lines and inserted the air-stones, filled the container with nutrient water and put the lid in place.
It has only been a couple of days so far so hope they do OK, I expect to loose a couple from the shock of moving but no biggie, to be honest I don’t even need most of these, it is more of an experiment.