blackskull seeds stardog

this is week 5 of flower - apologies for the late start on the diary! im new to growing and have just discovered grow diaries!😃 stardawg plants starting to bud nicely and put on some frost now, had a small problem with the tips burning/curling. i'm guessing this was a nute burn as have flushed since then and they're looking much happier! any feedback would be great though 😀