April 2019: For the past several months, the ficus pre-bonsais have been declining. The leaves looking lack-luster (literally), developing spots, some even curling up unevenly and the plant looking somewhat sad over all. This coincided with the re-potting I did probably last summer/early-fall, during which I used lava rock for the first time.
It also followed not too long after I started using LED plant lighting for 12+ hours daily.
I had also started watering plants with fertilizer laced water regularly. So I suspected it was one of these changes that was affecting the plants.
Around the same time, I had also re-potted the peace lily into beautiful new pot, and used lava rock for that too (since peace lily doesn't like soil going dry at all, and lava rock is good for water retention). Instead of improving, the peace lily started showing strong leaf burns and wilting.
The peace lily was never under LED lighting though. So lava rock became the primary suspect. Perhaps, there is too much iron in it, I thought. Or may be this Home Depot lava rock was meant as a mulch, and they had added some pesticide to it.
So a few weeks ago, I re-potted all these plants again, getting rid of lava rock completely, and flushed the soil with a lot of water to remove any doubts of lingering "iron" or excess fertilizer. But to no avail. The ficuses are deteriorating, and the peace lily is doing no better.
Then yesterday, I stumbled upon
spider mites in some forum. The phrases "dusty looking leaves" and "fine webbing" immediately rang a bell. Bingo! That's it. It's gotta be spider mites that are making my plants miserable. I took a magnifying glass to the leaves, and could see some irregular white flakes. Perhaps these are the mites. Don't matter - I decided to
treat the plants with insecticidal soap, and gave each leaf a good hearty spray. For cuttings in development, I gave a spray of diluted rubbing alcohol.
Now it's wait and watch. I'll probably give these plants another spay in a couple of days. And really hope these plants improve.
June 2019 Update: Happy to report that most plants are showing marked recovery after repeated spraying with mostly rubbing alcohol + water. The ficuses are almost back to normal, and starting to look really nice. But the peace lily us still sad. So it may be going through some other issue - not really the spider mites...