Petrushka that information was so helpful! Thanks so much for taking a look at the link for the soil mix and weighing in. I went ahead and ordered three bags of it based on your assessment. I have three 3-foot plastic window boxes that I will place side by side across the ledge. They will definitely be heavy once full, but the reservoir is refillable from the top so hopefully I can just use a watering can to do that and it won't be necessary to move them. The ledge is simply a visual divider between by living room and dining room which both have 2-story ceilings, so there will be open space on both sides of the planters as well as lots of open space above them. While I know I'm pushing my luck with 12 feet between them and a light source, there are large windows on both sides of the ledge (a large one in the dining room and two on the opposite wall in the living room), so at least they will have light coming in from both directions. There is also a very large wall-sized mirror on my dining room wall adjacent to that window, and my walls and ceiling are a pale cream color so that all helps reflect natural light and make the room a little brighter. To give you a better idea of how much light I'm working with, throughout the day it stays light enough near the ledge that one could read comfortably without switching a light on, but there are never any spots of concentrated light on the walls at any time during the day... It is all very filtered (and dim enough to feel slightly gloomy, so I always have lamps on when I'm in there even though I can see fine without them.) After doing some more research I'm now leaning toward buying Philodendron hederaceum (which I had thought was called Philodendron scandens until I read more of that very informative blog you linked to!) instead of the Syngonium I originally asked about. The sunlight issue is my biggest concern at this point, but I've been encouraged by several anecdotes about P hederaceum thriving in conditions even dimmer than mine, so I'll give it a shot (and probably have my husband remove the solar screen from the dining room window for an extra light boost). Cautiously optimistic!

I don't get it, why don't you want to water near the main stem? For sure though, squashes put down aventicious roots at each leaf joint that touches the ground. And you want those roots to draw moisture and nutrients. If you grow vining squash in a well-prepared and moist spot, and let the vines travel over barren, dry, hard soil... those plants will wilt on warm/dry days. If instead the vines are able to draw moisture all along their lengths, they draw plenty of water to prevent wilting. Some people say the wilting is natural and that's true. It's a natural reaction to water depravation. Having said all that, in the typical back yard it's impractical to cultivate such large areas that vining squashes will cover. I try to give each vine at least 3 or 4 feet in every direction of soil that is fertile and watered. After that, they're on their own, and some wilting will occur.

Can you post a picture of the situation?

Thanks Digdirt, I agree that it'd probably be easier to just get slips from potatoes in the spring. The problem is I've never tried this with these varieties. I don't know if they're "Rare" but they're certainly not easy to get. The Okinawan sweet potatoes were really difficult to find and I had to resort to getting them from a guy on ebay (he was the only person who had them) after the one online website I bought them from basically said "sorry, our crop failed, try next year". This was from rareseeds.com, which I found to be the only seller that year. I guess it only being on "rare"seeds, suggests they are in fact sort of rare, don't know. The Murasaki Japanese Sweet potatoes are a little easier to get, but tend to ship late. I live in North Texas, so we're used to Beauregard's and such, but these Japanese varieties (super delicious by the way) are unknown territory for me, and just too difficult (and expensive) to obtain again. Organic versions of these potatoes are impossible to find since both of these varieties are irradiated at the supermarket. I've yet to find anyone that sells these at a farmers market as well. My crop this year wasn't great since they got started late due to issues with the suppliers, and I got maybe only 3 or 4 meal sized potatoes (of each variety) and a lot of tiny little tubers. So basically I have no idea how this crop will do as far as giving me slips next spring. There's a lot of "firsts" going on here, and I'm also curing them for the first time as well. If I have to plant them in soil, I'll do so, it's just they're so much easier to get going in water and I'm afraid I'll lose my cuttings if I transplant them. They're taking on great (root-wise) in water right now, but some of the leaves are starting to yellow, don't really know why. 5 months is a long time to overwinter though, so I guess I'll just try to cover all my bases and plant some in soil, keep some in water and hope I get slips from the tiny tubers next spring.