Given your situation, the 2 most likely issues are over-watering because there is no drain hole, spider mites because Hedera is typically a mite magnet indoors, or, if the planting has been established for more than a couple of months, the salt build-up Alison mentioned. Weak plants don't usually yield cuttings with a high success rate, but because ivy has pre-formed roots that occur at every node, you might snip the terminal 5 nodes, snip the leaves off 3 of them by cutting through the petiole (leaf stem) close to the attachment point, and potting it in a conventional pot with a drain hole and fast draining medium and putting the cutting outdoors in open shade and out of the wind. I would take the remaining parent pot out of the pot it's in, remove the old soil, and also repot that in a conventional pot with a drain hole and fast draining soil. After the cutting roots and/or the plant recovers and they start pushing new growth, you can start regular applications of fertilizer. PS - it's VERY easy for roots to get over-heated in a clear container - your set-up is essentially a passive solar collector. If any direct sun hits that container - it's a problem. Al

Dry, droopy leaves and a dying plant are often the result of overwatering. Does your pot have drainage holes and are you letting it dry out between waterings? Other than that, it could be any number of pests such as mealybugs, spidermites, scale, etc. Have you noticed white puffs on the leaves or stems or on the roots, or is your plant secreting a sticky substance? If so, be sure to wash your cuttings with lukewarm soapy water before rooting, and be sure to wash your pots in bleach before repotting the cuttings. Other than that, it's kind of hard to guess the problem without seeing the plant and examining it up close for pests.

Houseplant, ivy's need a well-draining soil..You do not want soil to stay wet..By doing this, ivy will indeed get spider mites..While you're at it, check the ivy for this insect..They can devour an ivy in days..Look for webbing, the main indication of mites. I mix my own soils using all purpose, sand, peat and perlite..You don't need much if any peat in the mix..I'd unpot, remove dead leaes, place in a bright but cool location..If you can place plant outside until late Sept/Oct the better. I keep my Ivy's out late in the season..When you think about it, there are hedera's that are hardy to z5. It's important to mist leaves daily, especially in winter once the heat is turned on in your house. Check out www.srtopiary.com They've a good number of ivy's w/pics, so maybe you can ID yours..I just bought 4 ivy's from them and boy are they nice,.3 will grow as topiarys, and one will be mixed w/my 10 yr old Algerian ivy. They also need circulating air..My house isn't ac'd so I use fans..Good luck and keep us informed on your progress..Toni

I hate to crush your enthusiasm but I can see nothing but difficulties with this idea. Even outdoors getting four solid green walls is a tall order. Things to consider: Light: Even ivy needs light and unless your room has a glass roof there is unlikely to be enough light for plants on every wall. Growing medium and containers. To have ivy over every wall you would need pots or troughs all around the room. Access: If you have trellis 1 inch away from every wall how will you access power sockets, light switches, etc? How will you clean/redecorate the walls? Dirt: Indoor plants do not get rained on so somehow you will have to get the dust off your plants without damaging the wall beneath. Free standing or hanging plants can be rinsed off in the shower but yours will be permanently stuck to the walls. Aerial roots: Ivy is a self clinging vine. It will not stay on the trellis but will try to stick to the wall. Time: to achieve this effect would take several years providing all else went well. I have seen this done on internal courtyards (no roof.) But only with undecorated walls to which the ivy sticks by itself and in a milieu where hosing it down periodically to clean the leaves does no harm. If you go on over to the Houseplant Forum you can ask some of the regulars to post pictures of their rooms. Some of them live in mini jungles. But the plants are not fixed to the walls. Here is a link that might be useful: Houseplant forum