In Mississippi your options for sweet potatoes are almost unlimited. Northern growers have to work harder. They are very undemanding as to soil types. In my youth, they were commonly relegated to newly clear land (Newground). They do need to be planted on elevated soil, normally lists about 4 inches high and twelve inches wide. I plant 14-16 inches apart on 4 ft. centers. They don't do well on a flat surface especially in heavy soils. I start planting in early May and can plant through June. I grow most of my plants in a sunlit cold frame but do order experimental varieties from George's http://www.tatorman.com/ , Steele http://www.sweetpotatoplant.com/ and if I want something exotic I will order from Sandhill http://www.sandhillpreservation.com/pages/sweetpotato_catalog.html. They are very late shipping and only offer small numbers so I use them just to get starts. They have the widest selection of varieties available. New Hope offers plants but I have not tried them http://www.newhopeseed.com/sweet_potato.html.
They can be harvested anytime they are big enough for your use but before frost kills the vine. I usually dig them in September_October. They do need a couple of weeks of warm weather to cure (lose thier excess water content) I just throw them in the barn. After curing they just just a dry place that does not go below about 50 degrees. They can't take much cold.
As for variety, that depends greatly on your taste. Southerners generally prefer the moist orange fleshed types that are often called yams ( they aren't of course) Yellow or white varieties are preferred by some northern folks and ethnic groups. The oft mentioned Nancy Hall was grown alongside the Porto Rico in my youth. Never cared much for it as it tastes more like a winter squash than what I expect a sweet potato to taste like. Ditto for whites as I have grown Poplar Root, White Jewel,White Triumph and Violetta. White Jewel is the only one I really liked. The old vining Porto Rico has the best flavor for me, but is prone to scurf on my soil. I like Copper Jewel, Centennial for production and good flavor. carver is productive and I grow them, but not as tasty as the aformentioned.
Jewel {{gwi:14251}}
Poplar Root {{gwi:26910}} Beauregard {{gwi:92327}} Sweet tator patch {{gwi:92326}} Violetta {{gwi:114914}}

farmer has done a fine job here covering much of the field.

Up north I planted some in May and my home grown slips were late [superbly rooted though] and planted about June 10th, but these did equally well. All grew quite large. Sweetpotatoes need a ridge to keep them in a drier soil which helps prevent scurf. I go for a 12 inch ridge and this greatly assists digging them.I use a black plastic cover on some to keep them drier.

I raise mostly O'Henry which cooks to a very smooth light yellow. I have not found an orange that appeals to me...neither a white [no flavor].

Trellessing is something I know little about, but be assured that most healthy sweets will send out a huge amount of vines about 10 feet long.

If you have deer in your area. You need to plan on protecting them! I haven't had a very good crop in years due to deer.

IMO, Glen Drowns at sandhill preservation gives the best info available on the net regarding sweet potatoes. The tip I got there about keeping slips soaking wet for the first 7 days after planting out is invaluable.

Orange, white, yellow, obviously totally subjective. I think 100 years ago all types were grown in all regions. Fearing Burr was growing sweet potatoes in MA in the 1840's, and storing them through the winter. That is the big issue for northern growers - storage.

My sweets are curing right now...84F for 8 days.

Yep, preferred browse for deer. One more tidbit. Varieties are available in bunch form as vine form. Vining types can have huge vines. The old Poplar Root will head for the next county, wheras the White Triumpth which some folks try to pass off as Poplar Root stays under three feet.
Carver has very small bushy vines about 2 ft for me. {{gwi:114915}} {{gwi:114916}}

Not only will the deer browse on sweet potatoes, but they will also dig them up. This year, they have pawed the ground and unearthed the potatoes and nibbled them. Voles and mice can also be huge problems. Voles will do their damage underneath the soil while the mice eat from above. My favorite varieties are Beauregard and O'Henry. They don't split and are usually found straight under the plant. They are vigorous and can withstand browsing pretty well too.

Keeping weeds out have always been a problem for me. This year I decided to plant them into black landscape fabric.

One of the best things I did all year!

Here it is before planting.

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Same plants in mid June
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Mid August
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What it looks like under the fabric before digging.
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Harvest
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This was a new area and I didn't get it tilled deep enough so the plants didn't grow very deep. Also I think my hills need to be wider next year. They were 12-15 inches, probably going to go to 18-24 next year.

Just an FYI, I buried drip tape under the plastic. I spaced the potatoes every 12 inches, right beside the emitter. It was also easier to cut a "T" shape to plant the slips than it was to cut an "X". Only problem was with mice. I am guessing my loses would have been less if I dug them all at once instead of spreading out my harvest window to 1.5 months.

Jay

I guess I was lucky no mice or voles under my fabric. probably will have problems next year if I go into the old pepper and tomato beds.

I just dug my sweet potatoes up tonight. I didn't have such good luck. I'm in MA on the north shore, and we've had a couple of very soaking weather patterns. Last week, we got 5.5" of rain in 2 hrs. I was waiting for a dry stretch before digging the sweet potatoes that I planted in my community garden, and when I went to check on the plot a couple days after the huge rain storm, many plots were still under water. Mine wasn't but it was quite wet. We had a dry stretch, which is supposed to end tomorrow, so I went and dug tonite. The soil was still very wet, and most of the sweet potatoes at the top were rotten :( I grew georgia jet. I had only 3 slips, this was my first year growing and I didn't want to take too much space. I planted them May 21. Maybe next year I'll build raised beds, which will allow more drainage? I did get a few nice sized sweet potatoes, and quite a few little ones I'm not sure are worth keeping. I don't have anywhere to cure them that is 80 degrees, the best I can do is my basement, which is the 70's. Will this be OK?

michel, since you have so few maybe just leave them on a sunny windowsill for a week and then in the basement.

For next year try making some high ridges, and May is too early for northern MA, wait until early june. Nights should not be below 60.

If you want to re-use potato soil (as from potato bins), or other specially made soil as well, you can sterilize it with boiling water. How to do this is explained in the Storey Bulletin "Potatoes, Irish and Sweet" -- Storey Publications in Vermont. 5 gallons of boiling water will sterilize about half of the soil that stores in a 55 gallon drum, so about 25 gallons of soil. My potato soil is too specialized and costly not to re-use it!

BeanGrower, This brings me to the question: Have you had disease problems with your "soil"? Are containers more likely to harbor disease?

Killing every trace of soil life by inundating it with boiling water would be unfortunate, and quite unnecessary.

Thanks pnbrown. If we have some sunny weather soon, I will put my sweet potatoes on a warm window sill. I see you are also in MA, so you know our weather. I am definitely trying again next year. I did do somewhat of a high ridge this year, but definitely not high enough. Our community garden has a slight slope down, and my plot is close to the end of the downward slope. So, I'm thinking a raised bed will work better. I do have a home garden also, but the community garden gets much more sun, so I do onions there, and now sweet potatoes. Also, since there are occasional stealing, I grow things less appealing at the community garden.

I would voice rousing acclamation for Okinawan.... Unfortunately, it takes 140 days to mature so is only viable in zone 8 and further south. I can manipulate the plants and get them to mature here in North Alabama, but it is touch and go every year. The trick is to start with rooted cuttings in cups and get them in the ground as early as the soil temp will allow.

Mahon is a new one for me this year. I really like the looks and shape and production. They will be cured enough to sample next week.

I've grown a few dozen varieties over the years, but have not found any particular variety that is overwhelmingly better than others... excepting Okinawan.

DarJones

I expect the bigger issue will be to properly amend the soil to make up for what the last crop took out.

Dar, you have peaked my interest! probably I have more than a long enough season at my central fla place for the okinawan. Is it orange flesh or white?

Purple flesh. Definitely different but I have not tried growing them. Dar is more into exotics than I am, so if he says its worth a try, its worth it.

I happen to love the okinawans though not for the standard candied sweet potato dishes most folks make. They make a sweet potato pie and sweet potato casserole that is very good. You can also make purple sweet potato ice cream and a host of other dishes that are popular anywhere Japanese cuisine is common. Okinawan is often used as a base to build a complex dish like a casserole with sweet potatoes, bananas, butter, and brown sugar.

DarJones

Dar, is your listed email working?

Wow. Thank you to all of you. This is completely fascinating! I am printing out this thread so I can digest it through the winter. It really doesn't sound hard, just need space, right? I am thrilled to learn that there are some bush varieties too. That will make it much easier to work some of these plants into my raised (perfect!) beds. Blessings to you all!

I harvested the Mahon's today. This is a very impressive sweetpotato. The typical production is 5 nice size sweet potatoes per plant and there are another 4 or 5 small roots of a good size to be candied. The largest will weigh between 2 and 3 pounds which puts it in a perfect baking category. Most important, it cooks as good as it looks! This is one variety that just made my grow every year list.

DarJones

Smooth and dry, or moist and stringy?