(Note: I didn't have time to gather some photos for today, but if you're interested in pictures, I will upload some to this post tomorrow. Just check back sometime later. Thanks.)
"D" sent me a list of questions about sweet potatoes. Luckily, she also lives in Hawaii, which makes answering a whole lot simpler for me. While I'm no expert on growing this crop, I do indeed grow a lot of sweets. Basically I use the greens for livestock feed, but I also harvest the tubers. Plus over half the sweets I grow serve as a cover crop or living mulch.
Above, sweets used as an aggressive ground cover. This one produces 15' to 20' vines, grows quickly, produces lots of side shoots, making it ideal for a quick ground cover.
Question #1- "Any specific time to plant?"
I've planted cuttings in every month with success. They always root. Their growth may be slower during early winter, or when things are dry and windy, but they don't die. They just wait for better conditions. My latest cuttings were planted in January and they're actually looking pretty good. Not at all stunted. If I had to name a month or two that are the least desirable for planting, I'd say November and December. Growth is slow those two months even if all other factors are even. But I don't hold off planting cuttings if I have them in Nov/Dec. Nope, they go into the ground anyway. Now for the best months to plant? For me I'd say Mar-May.
Question #2- " Where you get starts?"
99% of the time I use tip cuttings from other plants. When I harvest or thin my sweets, I'll choose the healthiest tips to make cuttings, about 12"-14" long. I'm looking to plant at 3 or so leaf nodes into the soil while having 2 leaf nodes (plus the small tip) out of the soil. Usually I make the cutting and place it into fresh rainwater for 3-5 days until I see roots starting. Then I plant the cutting. You don't really have to wait for roots to develop. The cutting can immediately go right into the ground as long as you give it a good drink of water.
Occasionally I'll make slips. Making slips means planting the tuber and havesting the shoots that come up. Those shoots are what is meant by slips. I'll snap them off the tuber when they are at least 6" long and plant then. I'll do this when I'm given a new tuber variety to try. On the mainland where it is cold, gardeners don't have vines to take cuttings from. Thus they plant the tubers in a warm area and create slips for transplanting out in their gardeners.
I remember as a kid suspending a sweet potato in a glass of water, using toothpicks as props. Then over the next couple of weeks watching the sprouts grow. I guess we kids lost interest after a couple of weeks, because I never recall planting any of those slips.
Question #3- "white versus purple versus orange"
All. I like to experiment, so I grow all sorts. Sweet potatoes are highly variable. The skin can be white, creamy, gold, orange, red, pink, purple, even blotchy. The flesh can be white, cream, orange, purple...ranging from pale to intense, and adding streaks and blotches. Not only the color is variable, but all sorts of other traits too. I have tubers that range from smooth to lumpy, round to snakelike, big to small. Some tubers are oh so pretty, others are downright ugly. Some varieties are good for baking, others are better for mashing, and other yet better for frying. Some are dry fleshed when cooked, other very moist. And anyone who has grown several varieties of sweets will tell you that some varieties are incredibly sweet, others mid-way, and yet others not so sweet at all. Some varieties produce lots of tubers, while others produce very few. Some have blocky roundish leaves, others handshaped leaves, others thin lacy leaves. Some plants are thick and robust, while others have thin somewhat wispy vines. Plus there are bushy varieties, and aggressive running types with incredibly long vines, and dozens of intermediate length vines. Some sweet potatoes mature early, others very late, plus lots of varieties maturing somewhere in between the two extremes. Boy, there sure is variety in sweet potatoes!
So back to the question, white vs purple vs orange. It comes down to personal preference. With me, it depends upon what I'm doing with the tater. Hubby prefers the non-sweet ones. I like them all.