Something happened while being away...help!!

Please help! I have this plant which is very special to me (same age as my 6 years old child). I was away for 4 weeks, somebody would water it every week and I don't know what happened but is dying. Not sure if it was the weather (it was -20C average and the plant was close to the window so it could get sunlight, but inside the heat was set to 15C). Before I left the plant wasn't doing very good either. It had this layer on some leaves like dust and it looked dull. Right now it looks dry and I hav another 3 plants in the same situation. I know just how to water them so I feel lost and need to know if i can do something to save my plants, thx!

Is it in a free draining pot? Have you tried feeding it? Is it pot bound?

Looks like spider mites maybe...do you see little tiny webs?

It is not in a free draining pot, it is actually a small pot but is not pot bound. About two weeks before I left I started feeding it with Miracle gro, an all purpose plant food 15-30-15, and I left the solution ready for my friend to water the plants.

I don't see any webs, but I do recall seeing some on another plant, I think over the last summer. I just cleaned the leaves with a cloth at the time, and the plant was fine. Both plants have been in the same corner at different times. Here are my second and third plants in problems, they look as the first one I posted. The one on the left was the one with the webs.

You might need to take them into the bath and wash the plants and soak the pots so that they will absorb water completly. Don't fertilize them until the are well recovered from this.

There definitely could be spider mites, but on top of that I have a feeling there was probably some overwatering going on. If some of those pots don't have drainage holes you definitely ought to repot into something that does, and for the one that looks like it does have drainage but sits in a tray you need to make sure that you drain excess water out of the tray rather than letting it sit in there (whoever was watering your plants for you may not have known that).

I agree with ecrane3.They definitely look overwatered.Also,plants should not be fed frequently (if at all),this time of year.Exceptions would be plants grown under lights.It is best to use very weak solutions of fertilizer on most indoor plants,especially under lower light or cooler conditions.

Considering your location, and the fact that you were away for 4 weeks. You said you had the heat set for 15C which is roughly 60F. Maybe they got too cold, some tropical plants do not appreciate that low of a temp. for prolonged periods...especially if they were also being watered and fertilized!! It could be a combination of everything.

Most tropicals should be fine with 60F all by itself if there aren't other complicating factors--I have a whole greenhouse full of things that gets down into the mid-40's every night and they are all happy and healthy. I have a Schefflera in my house where I keep the thermostat at 62 during the winter, and it's next to a window where it's probably a bit chillier. And I had one at my old house that lived outside and saw temps in the low 30's. But if that house temp is much cooler than usual then the plants won't go through water as quickly as normal, so if they were being watered at the same frequency as you usually would then that could account for the overwatering.

So, what should I do if they are overwatered? Can they recover from that? And then for the spider mites, which after reading all your feedback I think that's part of the problem, I should wash the plants, right?. And I also read that I should keep spraying them to keep them moist, and also that I can use a solution of Neem oil, dish soap and warm water if the problem countinues. But the question persists, can they recover?

Whether or not they'll recover from overwatering depends on how badly the roots rotted before the soil dries out a bit. If the soil is still really wet, often the best thing for them is to repot into some fresh dry soil. Plants can also recover from spider mites if you catch the problem in time--if you have leaves that were badly damaged before you caught the problem though they will eventually die completely and drop off the plant but the plant will grow new leaves. I would treat for the mites, make sure you're watering properly, repot if the soil's still sopping wet, and hope for the best.