How do you determine when it's time to water? It looks like the result of excess water in the soil for extended periods; and, a high level of dissolved solids (salts) in the soil might be a contributing factor. When your soil is too wet, it limits your plant's ability to take up water, which results in a drought response. The first thing most plants do when threatened with drought is start shedding leaves to conserve water, even if the roots are drowning in a sea of plenty. Too, high salt levels in the soil work in combination with an excess of water to further limit water uptake. Enough salt in the soil can actually reverse the movement of water into cells and actually pull water out of cells (reverse osmosis) in exactly the same way that curing salt pulls moisture from meats like ham/ bacon/ jerky, ..... When you water, you should water thoroughly, so at least 15-20% of the volume of water required to fully wet the soul exits through the drain hole. Then, the plant should never sit in the effluent (water that has moved through the soil and out the drain). That practice provides a pathway back into the soil for all the salts that were flushed from the soil when you watered. In passing, it should be mentioned that root congestion causes loss of older leaves, as does decreasing light levels, but given the rotted appearance of the leaf stems, I'm thinking your issue is related to poor root health. You might lift the plant from the pot and inspect the roots to see what condition they're in, and start using a 5/16" wooden dowel rod (any hardware store), sharpened in a pencil sharpener to test the soil's moisture content. Stick it deep into the pot. If it comes out wet or stained dark from the soil, withhold water until it comes out almost completely dry. There will still be sufficient available water at that point to satisfy your plant's need for moisture. I think you'll find the info below to be helpful. Growing Overview Sick or Dying Plants? Al

is it in pure peat moss??? i dont know what it is.. but i wouldnt grow anything in straight peat ... there arent many things that prefer such acidity ..... tip it out of the pot.. and see if the roots are happy ... snap a pic .... and stuff it back in the pot for now... post us the pic ... what you got away with outdoors.. might not work indoors ... im curious about the greenhouse setup up.. you brought in the house.. if you care to share with us ... ken

can we see a broader pic of all the plants near it .. its classic signs of etoliation.. aka.. elongation due to lack of proper light ... but one would not expect such in a south facing window.. unless the issue is the shears .... might need to find a different spot for it.. or if they are all suffering.. maybe you will need to open the shears once in a while ... though to our eye.. a shear might SEEM to let in enough light.. that doesnt mean its USEFUL light to a plant finally .. is there a heat register under the window.. and is blasting this thing now that the furnace is on... see PS ... ken ps: BTW.. in every post.. tell us w2here you are.. big city name .. e.g. maine winter light is not like tampa winter light.. etc .... its usually not an issue with houeplants.. but in this case.. it might be ...

It isn’t either; it looks like a Columnea or Nematanthus, but could also possibly be an Aeschynanthus.