Yellowing into flowering only 18 days

[Justones]

FYI let me disclose this is my first time grow.

I'm about 18 days into flowering & it's yellowing fast. I read that this will happen, thought it would be closer to the end though. From the bottom up. Lack of nitrogen is what I gather from reading. I got some blood meal & worked it into the soil a few inches down today. Is that a good thing to do? What else might help?

Info: outdoors & sun. Soil grown, 20x17 pots, ph vary from 6/7, is not an autoflowering. Been growing since march.

I hate to loose this being it's been growing so long & in the final stretch. I only have two females. One is way bigger than the other. I had one other big one but it turned out to be male. So it got pulled then ISO extracted. The bigger of the two females is having the yellowing issue more so.

Here it is now.

Here is how it was last week.

 

[highasyalike]

Nitrogen

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[Justones]

As suspected, thanks. I hope what I did helps.

 

[masonman]

Yeah, looks like nitrogen. She'll be fine. The yellow leaves may or may not green up. Look for signs it has stopped on other lower green leaves. How much blood mall did you add? She won't need much in flower.

 

[Justones]

I didn't measure it. Honestly wasn't sure how much to use. I just broke up the soil a few inches down around the pot. Then mixed/scattered in a few single hand fulls into the soil. Looks a bit better today. Some of the yellow leaves have fallen off. So far no others have yellowed.