You can start light feeding (1/4 dose) after about the fouth node. Just keep an eye that you don't overdo it. Work up from 1/4 dose as the plant grows.
Depending on what the manufacturer says, most people will do a F-F-F-W routine. Straight pH water on the fourth feed.
Depending on what the manufacturer says, most people will do a F-F-F-W routine. Straight pH water on the fourth feed.