Ive tested seed/cutting mediums multiple times using a wide variety of nutrients and found rockwool best for the strength and quality of the roots and canna seedmix best for the time taken for roots to appear out the bottom. In order, i would put it..
1. Rockwool
2. Canna seed mix
3. Jiffy plugs.
4. Root riots.
5. Coco or soil mixed with perlite ( there was pretty much no difference at all between these).
And with any of them i found that proactive root stim was the best feed hands down, second to that was a mix of canna rhizotonic and growth technology formulex!
Il post some pics soon ✌✌