When do you start nutrients

when do you start to use them, when u start to flower?

Anytime after about 2-4 weeks, depending on the overall health and vigor of the plant(s). If the plant or plants are healthy and growing, you may find it best to start at only about half the recommended dosage for the first feeding or two, then gradually work up to full stregth. Do not try to treat any plants that appear unhealthy before giving any nutes, BY giving nutes. That just means the initial conditions are not favorable, and force-feeding an already unhealthy plant will most likely only worsen the condition. If your babies are about 8-10 inches and at least two weeks or so old, and appear healthy and vibrant, you can start giving them their "vitamins"to promote healthy, strong growth.

check your soil, some soils already come with nutes , such as 'miracle grow'. if ur soil has them then your not going to need to give them extra for a couple of weeks. i've just put my plants to flower after 5 weeks vegging and i only fed them in the last week of vegging. every plant is different and some people only feed nutes every other watering. this cuts down nute burn and reduces ph fluctuation as well.