Week 4? autoflower Ak47 x diesel Help.

Bottom leaves turning yellow, with a brown spot.
You guys think its nitrogen deficiency?
Its been on week 2-3 of flowering.

Here are the problem leaves

Yeah, lookin like N deficient buddy

even tho it's flowering? i thought they only needed allot of nitrogen when they are vegging?

Thanks im gonna go out and buy some nutes.

Well its true that they need more N during vegging, they still need a bit during flowering. I know that the lower leaves die off during flowering, but not quite sure thats whats happening here. I'm not very familiar with autoflower strains so l'm not sure about when they should start dyin off

i know this is late but this is defo a nitrogen deficency
ive done the same as you bought flowering nutes for my autoflower as i diddnt think they would need the veg nutes.
im intrested in seeing what you did, should i flush and adjust my nute soloution compensate for the missing nitrogen with something else??