Germination Questions


Hi everyone,

I am growing romaine lettuce in a HPA system. I am about to begin germinating, which I will be using partially submerged rockwool media under a 24h light. I was wondering if anyone has experience transplanting the germinated seedlings to an open root setup once they are in the aeroponic system, as I am worried they will be unable to adjust to the change.

I am also curious as to where the cutoff point for germination was for you; aka how long/how the roots looked when you decided it was time to move them to the HPA. Thanks!


Hi Bromblin
When you see roots outside the rockwool you can move them to aero. When they are in aero use the rockwool to provide a water reserve (safety net) for the plant while it establishes enough aero structured roots to support itself by mist alone. In practice it simply involves keeping the rockwool moist by top watering. This allows you to run low level mist outside the netpot to encourage aero structured root growth, think of it as 2 seperate zones, Once the plant is being supported solely by mist alone you can let the rockwool dry out. If you overmist, youll get a hydroponic root structure which takes more resources and grows much slower than delicate aero roots so you lose time. Converting hydro roots to aero costs even more time so its a double whammy. Its much less stressful for the plant to use the rockwool in the netpot for basic life support while growing the specialised aero roots it needs to explore the aeroponic environment beyond. Id recommend trying it both ways to experience the differences first hand :wink:


Thanks Atom! Just to be clear, when you say top watering, you mean just standard non-misted watering from outside of the container into the rockwool, in addition to misting? Or is it something else


Just enough to keep the rockwool damp so the plant doesnt stress about water, a syringe is useful. You create the low level mist environment outside the netpot to entice aero roots to grow out of the netpot. You can think of the rockwool roots as temporary or expendable. They serve one purpose… to keep the plant upright and happy while it grows enough aero roots :wink:


How is your lettuce doing?, Post some pictures, Personally, before i go lettuce all the way, i am doing Cilantro, Arugula, Basil, Parsley. They are all fast and a bit more forgiving…meaning you have to fire on all cylinders before a lettuce plants makes a head of lettuce. That way you can dial in your system…and achieve that Root growth that Atom shows all the time…lol Iam quite envious.