yea its too much nitrogen...u can either transplant or heres what ive done growing marijuana in that stuff: Wait till the plant show nitrogen defeciency before you start feeding again, this is indicated by an overall pale or yellow look of the plant, it is fixed quickly and easily with one feeding...from that point on feed normally but you might wanna cut down to 1/4 dose..marijuana grown in soil needs very little if any nutrients to begin with so think super Conservative when your using soil from now on unless you have a soilless medium thats different. With SOIL I am often able to grow happy healthy plants if they are put into flower within the first 6 weeks by using only molasses and water the entire grow. My soil is a bit more rich then ordinary as I add a lot of amendments and start with fox farm ocean forest as a base but still just remember the plant will pull nutrients from any soil from 3 to 10 weeks with no feeding necessary.
if you have grown other types of plants before likely you need to give about half as much water and 25% as much nutrients when growing marijuana...Cannabis like it dry and they like little food.
dont worry man your still early in, this can end up being an amazing grow, plants in veg can recover just about anything...just get them looking pristine before you hit the 12/12...to much nitrogen can increase flowering time and reduce yield.
so at the least start giving plain water for awhile...at best transplant them into new containers ideally with soil that doesnt have the slow release...but dont listen to some people who say YOU CANT grow marijuana in MG or slow release because some of my best plants has been in that stuff..just do like i said and wait till nitrogen defeciency untill you feed..this plant below here was a miracle grown plant that had to much nitrogen in the begining from the time-release, i let it go deficient before i started feeding...in the end it yield 6 ounzes indoors when I usually only get 2 to 4 in my garden so a bit of an odditiy...this top cola was as big as my head.