Peperomia verticillata might be a possibility. I'm not that familiar with the limits of its' preferences, but it's a daggone cute plant I've enjoyed having around very much the past couple yrs. It was a very inexpensive little Exotic Angel plant from WM or L's. Propagates easily, blooms readily, though the blooms are only things that those who appreciate members of the Piper family would notice or appreciate. http://allthingsplants.com/plants/view/474678/Peperomia-verticillata/ P. dolabriformis has interesting clear spots on the edges of the leaves. The foliage on mine keeps shrinking over time. I suspect it would prefer a lot less light than the exposes I've offered. Also found as an inexpensive BBS plant. :http://allthingsplants.com/plants/view/473716/Peperomia-dolabriformis/

That isn't watermelon peperomia. That's peperomia frost. They actually like a lot less light. Mine is on the second shelf of a plant shelf and is about 18" from a grow light. It does very well and retains all its frosty color there. I sometimes ignore it for too long and it will wilt. Then I water thoroughly and let it sit in a saucer of water for 20 minutes. Then I dump out the remaining water and let it sit in the sink for a bit to make sure the pot has drained off before placing it back in its home. I suspect yours is either getting too much light or possibly too much water. My suggestion would be to cut off all the ugly leaves. Also cut off all the inflorescenses because they drain energy from the plant. Then put it in lower light. Let it dry completely before watering again. You might want to also try to pull it out of the pot to see how the roots look. Hope this helps.

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 ...