any portion of tuber is sufficient so long as it is viable and produces slips, and yes if you know for sure tubers are viable they can be direct planted, but to be sure we use our method so we know we have viable material. the same with normal potatoes if they bud we know for sure they will grow. len Here is a link that might be useful: lens growing sweet spuds and pines

Thanks so much for all the advice and information grandad, toogreen, farmerdilla and wayne. It sounds easy indeed, now I wonder why we did not try this before. In the worst heat of the summer, only the okra looked good last year. I cannot believe that plant, flowering when it is 107 F!!!! crazy plant (I love it). This year we are adding cow peas and sweet potatoes to the hot weather vegetable clan. Why not? might as well take advantage of what grows well here and now. We cannot grow parsnips or cherries, so we might as well grow sweet potatoes. We have several roots (tubers?) starting, I only showed one, but we have white sweet potato and red sweet potatoes. They have different types of leaves, as shown in Farmerdilla's picture. Farmerdilla, your picture is nice, thanks for posting it. We might do a bed just like that, still have a few recycled pieces of lumber to use for garden beds. I think that 500 slips is a bit much for us, we might do from 12 to 20 slips. Since each averages about 6 sweet potatoes, this should give us plenty for feeding two not too large people. Besides, we are also growing other 'starchy' root crops, regular potatoes (to be harvested soon), jerusalem artichokes, chayote (the root is edible) and some weird tropical ones (elephant ears types). I take it that the level of development shown in the pictures I posted is just about right for taking the slips? not too large but large enough? or perhaps they could be 'harvested' as slips a little younger? We still have them in water but we will plant them in the ground, or in pots, this coming weekend.

As mentioned: "I believe you can plant slips into July. Just get an organic sweet potato from the market, cut one end off a bit, suspend (with toothpicks) in a jar of water....you'll have slips in no time. I don't think anyone sells 'slips'." :-O ------------------------------------- Metro Forum

I tried the "long slip process" a few years ago. I planted the ends off some sweet potatoes my wife used for a meal on Thanksgiving or Christmas. I plant the sweet potato ends in a plastic rain gutter I have across the inside of the kitchen window. By planting time I had many long slips that producer well. I have never tried the plastic mulch but I had planned to this year but I did not have any at planting time. I only have 22 of the Beauregard sweet potatoes and about 30 ornamental. Larry This post was edited by slowpoke_gardener on Tue, May 13, 14 at 16:06