How often do we need to fertilise our plants?

[Maxburns]

Dear All experts,

May I ask how often do we need to fertilise our plants and when do we know we need to do it?

Thanks!
;)

[Maxburns]

Add the dosage to every watering.

What do you mean & how do you measure the dosage cos I am currently using organic fertilizer.

Thanks!

:D