The way I start my tubers is simple but it has worked well for me the past few years. I put them into trays about mid April. The tubers are lying on potting soil but not completely covered. I only water when the soil is completely dry and I will only use a spray bottle, just lightly dampening the soil. Once they start showing green sprouts and hair roots, I move them to 24" planters or big round pots. I find it's important to put them in the planters head-to-toe so the roots are on opposite ends. Otherwise, they can become a snarled mess. I don't have enough sunny windows or enough grow lights for all the planters. I carry them outside every warm sunny day and let them harden off for a couple hours. After a couple weeks of increasing exposure, they stay outside 24/7, unless it turns cold. I just move them under the eave of the house at night in case of rain. I try to plant in early June. Biggest mistake I've ever made was starting them too early and ending up with a lot of tall, spindly plants that needed to be staked as soon as they were planted.
The planters in these photos had been sitting on tarps in the living room for a week while I was in Virginia. I had feared they might dry out, but they were fine except needing sunlight.
I think I'll try Geof's method and start a few in bags this year.
