True yams are from the dioscorea genus. They look very different from sweet potatoes. They’re oddly shaped and their skin is rough. They can have stubborn dormancy and hate the cool even more than sweet potatoes do (except for the hardy species).
I found “ratalu” purple yam at a local Indian store. I think this is synonymous with what Filipinos call Ube, which I believe is the species Dioscorea alata.
Getting them to break dormancy is an enigma to me. I think that ultimately they will do so on their own terms. They seem to want to be hot and humid, but definitely not wet. Finding the sweet spot in terms of moisture was difficult for me. They will rot if soaked for too long, and perhaps shouldn’t be soaked at all.
Mine started sprouting after the following procedure. I soaked them in water overnight (<12hrs). As soon as I took them out of the bucket of water, I dabbed them off and put them under a strong fan to dry their exterior. My thought process was to rehydrate them but prevent mold from forming. Then, after I thought their skins had thoroughly dried, I wrapped them in towels (intended to moderate the humidity from becoming too excessive) such that they were not touching each other and were completely surrounded by the towel. Then, I took the whole wad of towel-encased yams and put it in a single plastic grocery bag, loosely-tied, and placed it in a warm-ish location. Within a few days, I could see little round nubs starting to protrude from their rough, brown skin. When they emerged, the new growth was a beautiful bright purple.
Unfortunately, many of them also started growing a white mold on the outside surface. I freaked out about the mold and over treated them with elemental sulfur, which I think set them back. In hindsight, I probably should have tried gently blasting it off with water from the hose and/or treating with H2O2. Heck, maybe I could’ve just ignored the mold and just planted them as is. It’s hard to say.
It’s unclear whether anything I did induced their breaking dormancy. They may have done it without any intervention on my part.
They bounced back from the sulfur treatment and are currently doing well. I think I got lucky with the timing of them breaking dormancy which corresponded well with our weather warming up. In my Pennsylvania climate, I doubt they’ll be anything more than a curiosity and an ornamental.
Despite all of the finicking I did with these, I recently discovered a hunk of yam that I had thought was rotten and subsequently disposed of on the ground, completely forgetting about it. That was weeks ago. Just a couple days ago, I discovered that it had put down roots through the lawn and is growing without any special treatment whatsoever. What gives?
I’m hoping to be able to bring some of these inside and sustain as houseplants through the winter. The foliage alone is really pretty.
I didn’t have much luck finding any literature on this topic with clear answers or instructions. If anyone can provide any, I’d appreciate it. I figured I’d just experiment with them and thankfully I was successful at at least not killing them.
Also, David the Good has a lot of information on yams on his YouTube and blog.
Best of luck.
