Hey folks 
According to a Google search, this is a nitrogen deficiency.
Is that correct?
I’m using synthetic nutes & had been giving half strength dosages.
When I noticed the yellowing (4 days ago) I fed her at full strength 2 days ago, but haven’t seen any noticeable improvement as of yet.
I’m hoping I’m on the right track.
Any insights appreciated & will be noted.
Cheers, 
Yellowing can be N def but with a pattern like that (coming from centers) it needs more looking, digging up the leaf charts…
The curling dark green leaves often means pH problem, which can cause iron lockout, which looks like a picture matches your problem. I bet your pH is too high but cant say for sure, would like to know pH of runoff or of your soil
Pictures and charts like these are so handy when problems come up. Thanks for posting. Better than the one I had.
@Jaysittinback the PH has been around 6.3 - 6.6 every time. I do ph before giving any water.
If it’s ph like you suspect, what would your next move be towards resolving the issue?
Appreciate the insights by the way & the chart.
6.3 to 6.6 going in, or that’s pH of your run-off that drains out the pot?
If 6.6 or lower is draining out of the soil after watering, I wouldnt try to change it.
If I had to change it I would flush with a lot of clean water then start feeding again at over 1000ppm and mid-sixes in pH.
If nothing else I hope it’s not this… chemical injury. But youd know if there were lots of herbicides around
How often are you watering/ feeding and are you getting run off each time?
@TLC feeding every 5 days or so & never until run off.
Growth is explosive everywhere else which definitely seems as though it’s a nitrogen deficiency.
I’m just going to leave her I think & let affected leaves die off.
I’ve given her a good feed recently, so that should stop it from spreading hopefully. 
Of course, all input/insights are appreciated. 
Are you feeding a micronutrient product? That is an iron deficiency.
@MidwestGuy no I’m just using regular veg nutes. (Synthetic)
Iron deficiency? 
Yes, iron deficiency. You need to add a product that includes micronutrients such as iron, copper, boron, manganese,…
@MidwestGuy thanks I will look into that.
Do you mean in like garden fertilizer for vegetables
It looks like a deficiency due to lockout.
If it was a nutrient or ph issue I would expect to see all the leaves affected.
Not just a single leaf.
I’m leaning towards variegation which they will usually grow out of.
Just my .02.
