Just touch the bulb, if it is firm, it will grow, if it turned to mush, just discard it. I always start my begonias in pots. Do not have them burried to deep, just cover them slightly with soil and they will take off. I used to do a different method,starting them in the dark but found out this was just a waste of time.

I would be concerned about them rotting if they were under ground. Maybe if there was plenty of peat-moss and air (an inflated zip-loc?) around each tuber, so that any "sweat" would be absorbed they would be ok, and you would certainly need to make sure water couldn't get to them. i dont know when you can usually plant them out in zone 7. I usually pot mine up about a month before they can go outside, but here thats not for a while. It would allow the roots to get going, and you can snip down the stalks when you plant them out.

I had dahlias for the first time last year, and did a lot of reading about how to store the tubers. There were so many different ways that I wavered, trying to decide which to use -- and then we had a freeze and it was time to dig. It was getting close to Christmas and I was short on time, so after letting the clump (unwashed, just had the dried dirt brushed off of them) sit in my (55-60 degrees) kitchen for about two weeks, I dusted them with cinnamon (I read that was an antifungal but it could be an old wives' tale), tossed them into a paper bag with dry peat moss, and stuck them on the steps to the basement (about 50 degrees). I pulled them out this spring and looked at them . . . and they didn't look so good. Kind of dry and shrively. Even after looking at lots of pictures, I wasn't very good at finding eyes, and I certainly didn't see any on these. But, things oddly have a way of resurrecting themselves in my garden, so I went ahead and planted out -- the whole clump -- to see what would happen. One week and then two went by, and nothing -- I was sure they were dead. A week later -- foliage!!! I was thrilled. So, it lived!! Same story with my glads and cannas (my first year for those again) -- didn't look good, but came back strong. (Half the cannas had a little mold . . . apparently didn't deter them!) I don't know what a healthy tuber is supposed to look like after storage, but I think no matter what they look like I will always give them a shot! I don't have too many, so it's not difficult to do that. Was I supposed to moisten the peat? I did not do that. Humidity in the area they were stored was likely about 60% -- it's pretty low in the house but the stairs are above a damp basement. I'm also guessing that if I start the clump in a big pot, once I see some foliage, I'll be able to tell more easily where the eyes are? If that's the case, I can divide at that point to get more dahlias. The clump that started as a couple of tubers last year doubled in size by fall; it'll likely do the same this year. Anyway, I was pleasantly surprised that although I'm completely clueless, it seems like all (or at least most) of my overwintered tubers/bulbs came through. Surprised the heck out of me :). :-) Mel

If one uses peat moss to store tubers, you should not put them in cardboard boxes as the the boxes wick the moisture from the peat moss and then the tubers. Had you used peat moss in plastic bags and loosely tied the them shut, the moisture level would be the same as when you put them in the bag. When you use vermiculite, normally you use no water as the vermiculite holds moisture(that is why they add it to soil mixes). The additional water is too wet for the dahlias. The most often used successful method to store dahlia tubers is vermiculite and plastic bags and no water. The next best may be wrapping dry tubers in plastic wrap and the next best is the peat moss, if you can keep the moisture levels correct. The same goes for wood shavings and again, one would not moisten the wood shavings, and you must use plastic bags. The plastic bags create a vapor barrier that keeps them from drying out if the humidity is low or rotting if the humidity is high. Remember that commercial growers store thousands of tubers every year. You should be able to store a few successfully.