Lower leaves dieing

hey all i just wanna know if its normal for the 2 bottom spikey leaves to die on some strains of plant. Ilve heard it happens with some strains but i dont know. Im not talking about the embryoic leaves(round) Those 2 leaves r dieing on all of my plants.

thanks for any help

im not an expert but thats no problem ..i trim all lower leaves and have no problems .

I usually have the first set of single bladed leaves fall off as well as the next set usually 3 bladed, as long as new growth isn't slowed you shouldn't worry.