leaf problem, possibly over-fert. help please!

take a look at the pic of the day on the cannabis.com front home page. i have a similar problem on my leafs but no camera, so i havent been able to post pics. since that is what appears to be happening to my leaves, can anyone tell me what it is? i think what i have is over-fert problem because the leaves have this crispy feel to them like they are burnt, but its not from heat. I thought i might have had a magnesium problem also, but i think that magnesium deficiency makes the leaves have a softer, more wilted texture than what i have. any confirmation or help would really be appreciated. oh heres my medium- 50% peat moss, about 30%perlite about 20%, maybe less, of worm castings. also threw in a couple tablespoons of agricultural limestone. been using fox farm grow big 6-4-4 with the highest strengh so far being 3 tsp per gallon. did that about 3 times so far. plant is about 6 weeks. sorry for the long post

well now i think the pic changed...

I don't know this foxfarm stuff, but I've never put 3 tsp of any ferts I've used per gallon water. Is that the recommended amount?

yeah for aggressive strength....but im sure the directions arent specifically for cannabis so i suppose it is very possible that that was too much