Seed based diets are generally deficient in many nutrients notably vitamins minerals and protein. For on-going health and good breeding performance supplementation is essential.
The selection of supplements depends on exactly what your bird is eating.

Apart from seeds what is your bird eating?
Eggfood daily
Eggfood sometimes
Fruits and vegetables (including "weed" greenfood) daily
Fruits and vegetables (including "weed" greenfood) sometimes
Table scraps daily
Table scraps sometimes
Pellets
Practically nothing except seeds and nuts