Losts of things can be used as a fertlizer, my knew favourite one is kelp. I enjoy a kelp snack for myself but I bought a powder I dont really like and isn't the best food adative. Then I found some information on kep in the garden and a little really does go a long way. Kelp is one of the super foods that has a little bit of everything.
1g (1/4 teaspoon) of kelp powder
2.5L of water
Its best if you star with a cup of water and mix your kelp in then add the extra water. Water plants after the first true leaves apear, first flowering, at the first harvest and every 2-3 weeks after that.