Plants look healthy. IMA your soil has enough nutrients to last most stains 3-4 weeks. Including cal+mag. After that I would start feeding program at half strength. feed, water, water. when you water make sure you are getting some run off(at least a cup or 2). This helps flush unwanted salt build up. After a feeding cycle if plants look fine(no burn) then you can step up to full strength. When I switch to bloom nutes is when I will add a little cal+mag(2 tsp per gal.) In between feedings a few times. At the end of flowering use only water and flush the nutrients out as much as possible for a smooth smoke. Also look into drying and curing and learn how. This is one of the most important parts of your grow. Good luck.