Tropicals & Tender Perennials: Help my philodendrons, please, 0 by BigWaveDave

BigWaveDave wrote:
I haven't sprayed anything on them. However, I have been watering them by hand the past week or two because my drip is dead. Also we had a few days of blistering heat last week, so im thinking maybe its what Carol mentioned. For a while now I have only sprinkled a little ironite around them, so I wouldn't be surprised if they are micronutrient deficient. I'm going to start using my palm fertilizer on them. The one I'm not sure about is the 2nd philo pic I posted. It is in shade most of the day, but it might just need some good fertilizer. I noticed that some of its mature leaves were yelloing a bit. Here is a better picture of the new emerging leaf.

Thanx again for all the help.