This video shows how I plant rock wool cube seedlings into mason jars for the Kratky hydroponic planting method. I use quart mason jars spray painted black with chalkboard paint. If you want to make it look great you can use a chalk marker to write what the plant is.
For my new seedlings I use MaxiGrow hydroponic fertilizer. You will also need some mason jars and 3 inch net cups. To wick the water up to the rock wool seedling I put a base layer of clay pebbles. Then I surround the rock wool seedling with more clay pebbles to block out the light and wick water up from the bottom. Once your seedling puts roots down into the water you should be good to go. Keep a close eye on your water levels. Depending on the plant you will need to replenish the hydroponic solution as the plant uses it up.
Good luck and have fun!
