Hey bro, glad your trying ur shot at growing..
as soon as you can i would get rid of that tin cup and use something else.. if u dont have any plant containers lying around, you can just use like a regular mop bucket or something, clean and sterilize it and put some holes in the bottom..
and MG nutes will do jus fine, but once possible you might want to pick up some better nutes, and some soil too..
but ur plant looks healthy so you should be alright for the next two weeks.
your priority would be to get the soil tho, because with dug up dirt you dont kno what kinda bugs were in it or the ph of it..
and for your nutes...
for the veg stage you are going to want the nutes to be at a 3-1-2 or 3-1-1 ratio
and for flower you want a 2-3-1 nute ratio...
if ur on a budget i reccomend goin to home depot and gettin a bag of MG blood meal and some shultz all purpose plant food plus...
they cost under $10 together and will definitely do the job for your grow until you can upgrade..
good luck bro