7 weeks old? it looks lots younger. the dirt you are using looks like dirt, not soil, lol. try transplanting with some potting soil (or better if you can, but the way she looks, im guessing you dont want to invest a lot). are you putting her in a window sill? or taking her outside?
good luck! might try again with some better equipment, you will want to do it again, it is addictive to grow! lol
No one is going to know what's in it without sending a sample off to a lab. By sight, I could say that it contains very little organic matter so is likely low in fertility. Lower leaves that showed the various deficiencies fell off. I don't see a light green top, so the pH is either OK or a little low.
@tutuk007 As a learning experience, figure out the pH to see if you need to adjust it with some liming material (limestone or dolomite).
Then add a balanced fertilizer. At this point, liquid or something you can dissolve in water would be best. If it's not a made-for-cannabis fertilizer, only use 1/4-1/2 the amount recommended.