When is the best time to start adding nutrients? Or is it best to just follow the instructions on the bottles?
Bottle instructions can be misleading from 2 perspectives. What really matters is your runoff PPMs. If you have new FF soil then you don’t need nutes at all for at least 4 weeks. I’ll drop a PPM guide below.
Also, many of the nute manufacturers are pretty aggressive with their schedules. Again, measure your runoff PPMs and use that as your guide.
That said, do follow general guidance for the NPK ratios for your plant’s stages of life.
Below is a modified FF schedule.