New to the forum | New Gardeners | Hydroponics farming in India

Hi I am ganesh! from Chennai. I have taken to terrace gardening through the kit supplied by TN Government. It is almost 6 months since I started using the bags and have around 20 bags. I have only harvested greens so far from these nothing else like brinjal, chilli, beans, raddish etc were productive. They all vegetate well, flower well but dont turn in to fruits. I would like to know anyone using the TN "govt do it yourself" kit, if so what are the results?
I want to use only bio fertilizer, however the kit included 18:18:18 fertilizer which I did not find to be very useful. Please advice me about the fertilizer.

How often I should use fertilizer! and what are the other things I should do enhance the growth of the plant?