Feeding: I feed my plants when they are actively growing
e.g. during the spring and summer with
a standard inexpensive fertilizer (e.g. Phostrogen), adding a pinch to the water
before watering. Unless you are using artificial lights feeding is not recommended during the winter when the plants
are not growing.
However, note that a newly potted plant should be in fresh compost. It
will have plenty of nutrients, so there should be no immediate need to
feed. I don't feed plants during their first year.
Generally, with the cultivation of any plant, it's quite easy to get carried
away and over feed, and (generally again) this can be quite harmful to plants.