Things I've observed while growing sweet potatoes on my farm :
...From October 1st to March 1st the plants grow slower than the rest of the year. And the tubers tend to be smaller and less in number. This is no problem for me. If a home gardener notices this difference, it's nice to know that it's the time of year doing it, not their soil fertility or an inferior variety.
...While I can grow sweet potatoes year around, I see the most vigorous vine growth from mid-spring to mid-summer. The plants look absolutely gorgeous.
...My best tuber production occurs during early autumn.
...Sweet potatoes don't like soggy or wet soils. Mine do better when a little on the dry side compared to other veggies, but I don't let them get overly dry. They will however survive a drought. So I don't worry about watering the vines that I grow for livestock fodder or as a living mulch. I only watch the soil moisture on my tuber producing plantings. On years that I get 50-60 inches of rain where it is spread out during the year, I do not have to water the sweet potatoes at all. In drier years or during long dry stretches, I will water as needed to keep the soil from drying out.
... I don't use manure my sweets. Instead I use my "vegetarian style" compost. I found that by pumping the nitrogen to the plants, I ended up with some very weird looking tubers, lots of vine, and less tubers than anticipated. My standard vegetarian compost mix includes all sorts of weeds, grass clippings, waste fruits, kitchen garbage, coffee grounds, plus a tad of coral sand, lava sand, burnt crushed bone, biochar, wood ash.
...I plant cuttings 12" apart in rows about 3' to 4' apart. The rows is just so I can get in there to apply mulch for a few months while the vines are growing. If I'm just intending to grow the plants for livestock fodder, I'll plant even 12" in all directions, making a solid mat of growing vines. I will initially apply mulch when I plant the cuttings, but that's it. The vines grow too densely to be able to reapply mulch.
...The vines will often send out additional roots from the leaf nodes. These roots can form tubers. Thus one of the reasons some tubers are found far away from the mother plant. In order to encourage tuber production closer to the mother plant, I discourage this type of rooting. I repeatedly apply mulch, moving the vines to do that, in the process uprooting or breaking off any node roots. This helps keep the tuber production closer to the mother plant. It doesn't stop it altogether, but it helps.
...I don't have much trouble with pests. But they are out there, just not on the farm just yet. When I first started out I ignorantly planted weevil infested tubers. Luckily I noticed the problem the first year. I destroyed everything and didn't grow sweet potatoes again for 4-5 years. Since that time I haven't had a problem. But as a precaution I'm quick to mulch my cuttings, and keep the plants well mulched as a barrier to the weevil. The other destructive pest I have occasionally is the stem borer. I see a little damage from time to time, but not much. So far I haven't had to take action. And one last pest I've seen is the Sphinx moth. It eats the leaves. But they don't eat much, and I don't have scads of them, so I just let them be. Live and let live. For some reason I like those big moths.
...Diseases. I'm told that there are a number of serious diseases out there but I haven't had a problem so far. My preventative measures include in never bringing questionable sweet potato material onto the farm. I'm hoping to stay disease free.
...While curing harvested roots is the norm on the mainland, I don't do that here. The temperature and humidity in my house maintains the tubers just fine. And besides, I'm harvesting new tubers on a regular basis. No need for long term storage. When I harvest fresh tubers, I feed the old ones to my livestock.
Recipe from "S".......
For lunch I have created a very passable sweet potato dumpling, without salt and without other seasoning (a mistake).... dropped into gently simmering water for about 15-18 minutes.
One third cup flour, dollop of olive oil, dollop of canned cow, one elderly egg, and enough mashed sweet potato to make a thick, sticky dough. Made four. Need some sort of spices in the dough and should be cooked in stock. They were perfect dumplings, just a tad on the very, very bland side....