Background:

I've had this plant for about 6 months. It hangs indoors approximately 2 feet from a SW window in Ontario, Canada where the average indoor temperature is 19-22. Despite it's location, it receives only bright/medium indirect light. I have been watering approximately once every 7-12 days- usually until water comes out the bottom of the pot. Before watering I use a water meter to confirm that the soil is dry. I have not noticed any pests, and until recently the plant has appeared to be quite healthy.

The Problem:

About 2-3 weeks ago I noticed that the leaves/petioles were more curled (still rigid) than usual, and since then they have been progressively yellowing starting at the base of the plant. The leaves lighten in color, remain soft until 100% yellow, and then gradually dry up and become crisp. Upon noticing the color change I withheld water for 1.5-2 weeks out of fear that I had somehow overwatered, but the issue progressed. Last night I took the plant down, soaked the soil, and moved it to a slightly brighter location.

The yellowing leaves are not presenting with dark brown tips/edges, and the leaves at the soil line are going first. Is that an indication of underwatering rather than overwatering? I am skeptical because the yellow leaves are not dry and crunchy while undergoing the colour change, and I'm unsure of whether that's to be expected with this genus.

I am familiar with the symptoms of an overwatered/underwatered pothos, but this is my first time having to diagnose a philodendron. Are the symptoms of overwatering comparable in both plants? I'd greatly appreciate any experience you can offer that might help me interpret the signs. Thank you.

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