This is how we grow 18 cabbages vertically on aeroponic towers. 1. Rockwool: This soilless growing substrate is made from basaltic rock that is melted and spun into fibers. In its dry form, it naturally has a high pH, so we first soak it in reverse osmosis water adjusted to a pH of around 5.5–6.0, which is ideal for seed germination. 2. Cabbage Seeds: It’s extremely important not to sow more than one cabbage seed per cube in order to avoid overcrowding and competition between the plants later on. 3. Vermiculite: This is a naturally occurring mineral that expands when heated. It has an excellent air-to-water ratio, helps keep the seeds in place, improves moisture retention for germination, and is chemically inert, meaning it does not significantly react with or alter the nutrient solution. 4. Seedlings: After about three weeks, the seedlings should have 2–4 true leaves before being transplanted into the towers. 5. Transplanting: We never transplant more than two cabbage seedlings per g...