Falling cause leaf drop?

[Bill U.]

Was there any damage to the crown? Is the yellowing leaf separated from the crown in any way? It's odd to see the yellowing coming from the collar extending outwards. Normally when a phal is going to drop a leaf due to senescence (just getting old), it will reabsorb the nutrients from the tip of the leaf and work its way towards the crown... This has me a little stumped.

[lauraeli]

Originally Posted by Bill U.

Was there any damage to the crown? Is the yellowing leaf separated from the crown in any way? It's odd to see the yellowing coming from the collar extending outwards. Normally when a phal is going to drop a leaf due to senescence (just getting old), it will reabsorb the nutrients from the tip of the leaf and work its way towards the crown... This has me a little stumped.

It started from the middle of the leaf initially before it reached the crown Here is the first one i took so you can get a better idea.

There is no damage where the leaf attaches to the crown.

[lauraeli]

I have considered that the higher light from the grow light might have caused chlorosis, if the phal is nutrient deficient. That can happen in other plants. But then why would the new leaf be fine?

The yellowing did start on the highest point of the leaf nearest the light. But the newer leaf is obviously even higher and is fine.