PLZ !!! help, ak-47,white widow,sensi star

Hi i have been giving some plants, ak- 47 White widow, sensi star. I have never grown before, and whould like to know how , but i think i have plant problems. The ak-47 the upper leaves have realy thick rigges on them,and are folding up right down the center, the bottom leaves are turnibg brown, the plant is turning a lite green, the soil seems to hold the water, it's like the plant is not useing it. plz any one help.
the plant where given to me as a gift. and its starting to become a passion.kiss-ass

sounds like they got too many Nutes, possibly its the water that your using. make sure your water is pure. get some nice pure water and flush out the soil.(run water through the soil untill it comes pooring out the bottom of the pot its in. also. it helps alot to get the soil dryout well in between waters.....

More info needed> Pixs if possible. Lights, soil, nutes?