Yellow Leaves

My plants are 36 days into flowering and one of the plants leaves are almost all yellow is this just a nitrogen problem?

Yes but is also normal when your plant enters the flowering stage,
The plant focus on bud production (To reproduce w/ male pollen)
So the last of the plants worry's are to keep the fan leaves green
& healthy.

The plant is using more Potassium & Phosphorus & less Nitrogen,
You colud give it a tiny dose but a yellow leave here and there
is more than ok when flowering. hope I answered your question!

Jayy's

we switched to well water for more minerals .... can i just chop up a banana and put it in the water and pour it in it or what lol?

Hahahahaa that could work,
try looking for seabird guano I got a bag at my local hardware store
for only $3 thats a steal!

Jayy's