Vegetables Gardening - Growing Organic Vegetables

Hello,

I am wondering if small seeds like collards, kale, chard etc are planted directly into the soil, can I use pre plant and weekly feed mix in the preparation of the soil, or do they only get used with already grown seedlings?  

If the pre plant and weekly feed do go into the soil before planting the small seeds, would the mixture be too strong for the little seeds and kill them off by any chance?

Thank you in advance, Ines