Yellow spots and apparent purple reddish stems

I'm growing a small plant and it has some yellow spots, a few rust spots on some leaves and a few of the leaf stems are turning purple (not the main stalk). It's growing in miricle grow potting soil which I now understand is probably not the best and it has been getting both outdoor and indoor light for basically 24 hours a day for about 6 weeks. It's about 11 inches tall and I have no idea what kind of strain it is. In fact I got the seeds from a friend who had them for several years so I'm kind of surprised to have even gotten this far.

Can anyone tell we what if anything I need to do to improve this plant's chances of producing?

well the stems turning purple is ok (thats what cannabis does)and yellow leafs most like is too much nutes to much food or no light at the bottom.