dwarf schefflera arboricola dropping healthy leaves/stems

[Acen10]

Hello,

New to the forum - nice to meet you all.
I have had a dwarf schefflera indoors for 2 years now (history outlined below). It has been losing leaves and stems rather quickly in the past 1 month.

Location: zone 5 (USDA) - Toronto, Ontario
Pot size: 8-inches (year 1), repotted to 12-inches 10-months ago.
Water: Once/week when top inch feels dry
Light: South-facing, no direct light (year 1), South-west-facing, some direct light (year 2, we moved.)
No signs of pests
Never fertilized and potted in all-purpose potting soil. Drainage at the bottom.

The story:
The plant seemed to enjoy the summer where it would get late afternoon direct sun and has seemed healthy for 2 years. We were gone in November/December for 1 month - someone watered once/week for us but the blinds were closed - 1 month with no light! Mid-December we came back, put it to its usual position in the South-west-facing window (no direct light in winter, though) and it appeared it was still in good shape. End of December leaves started falling from the bottom of the plant. I didn't worry as there was still lots of new growth at the top. However, now 21 days into January, it has lost the bottom half of its leaves and the new growth is starting to fall off as well. All leaves appear perfectly healthy but just seam weak - a slight wind will knock a few leaves off!

My guess - not enough light? It is about 12 feet from the window (old house, cold draft) - would it be better to leave where is to avoid the cold draft or move closer to the window to get more light?

Any other tips would be greatly appreciated. Thank you.
(I've tried to add a picture - hope it works).

[imafan26]

A couple of things. Potted plants do need repotting once in a while it is probably time to change the soil, repot and fertilize. The roots may be pot bound so when you take it out you may have to trim or tease and pot up.
The leaves are dropping because of the changes in light, the blinds closed. It was in the dark for a week or more so the plant probably tried to go dormant. Your friend watered it once a week but in the dark and going dormant it was probably more water than it was used to. The soil would have dried out slower in the dark. When you came back you put it in its usual bright light postion. Transitioning from dark to light needs to be gradual, schefflera is pretty tolerant but it probably had another shock transitioning. Usually the leaves will yellow and sometimes drop when it gets tossed suddenly into more light.

I suggest after two years it is probably time to repot in new soil and with some slow release fertilizer. Indoors, I don't worry too much about having to put it in a shadier spot after transplanting and it is best not to keep changing its light.