fertilizer pellet question

i live in croatia so theres really little supplyes in the stores and its hard for me to find the right fertilizer ,just now i got some pellets 10-10-20 can i use them for veg. on my plants i have one 60 days old and 10 they are 23days old northern lights and afghani.i need some advice and how much can i put and do i need to use some aditional fert. that i have 10-5-8

Do what you gotta do B. I suggest you use the internet if you can't source locally. If that's just not an option, you should use fertilizer with the highest phosphorous rating you can find for flowering. If it's 10-10-20 that's cool but you'll have to use water only for the last 3(+) weeks of flowering. 10-10-20 will be good for all of veg and flower until/if you find a decent bloom formula. I don't know how much you should use; the plants can tell you that.

i just need it for veg. later on im puting them outdoor is 10-10-20 ok for veg and do i need the extra fert.10-5-8 or not

10-10-20 is perfect for veg.