NEVER give nutrients to cannabis seeds! In the early stages of cannabis plant growth, just as with any plant, nature will do its own thing.
From seed to seedling stage, a plant is delicate and does not need extra nutrients in addition to those it is taking from a good potting soil. When the plant has established itself, and is experiencing rapid growth during the vegetative stage, is the time to introduce nutrients to the feeds (extending this program through the flowering stage).
There are many nutrient products available for the grower to buy and a good manufacturer will provide a guide to dosage and frequency for different stages of growth.