GROWING SWEET POTATOES IN THE NORTH

[catjac1975]

I get this question from my local friends. I thought I would share my advice for any others growing in a northern climate. Sweet potatoes are very cold sensitive They are only distantly related to white potatoes, so their growth habits are very different. You can grow your own slips, I was not very successful at it but it really should be quite easy to do. If you choose to try that, you have no way of knowing if the variety you get from the store will do well in the northern climate. There are planting of online directions for growing slips. Sweets have different maturity needs. I only buy slips for 100 day sweets.I have tried all the types that I can found listed for 100 days. Only 2 grew to a good size. I only plant Beauregard and Georgia Jets, both are 100 day plants. I plant them out in the 2nd week of May, but I prep the soil before then. They like a slightly acidic soil, loose and well draining. Like most plants they need to be kept watered. I have been buying from Steele Plant company. I also bought from George’s plant farm. I only switched one year because of availability. I am sure there are plenty of companies out there.

Sweet potatoes are a lovely vining plant, that need a lot of room. I have read to heat the soil with black plastic 2 weeks prior to planting. Instead use reusable black weed blocking fabric. It heats the soil and provides weed suppression. I plant the slips in the holes that I make in the grow fabric THAT I use year after year.. You will need to do some weed pulling in the holes before the plants take hold. I begin harvest in late September, I am a pick and eat kind of gardener. I only dig the rest of the potatoes when the real cold weather is approaching. Then the sweet potatoes must be cured. But that is a tale for for another time.

 

[ducks4you]

DD grew last year's slips...with a sweet potato in her vegetable bin!
I have my last year's harvest, about a dozen smallish and skinny sweet potatoes. My research has suggested that I should start them THIS WEEK, in soil.
As soon as the sweet peppers move on to pots on top of the fridge, the sweet potatoes will be able to occupy my 4 ft long and 8 inch deep plastic window box, with lots of rotted compost from the Last sweet potato outside potting, and I will let them grow their slips and vine down my growing shelving unit. They won't go out until June, but should do well with the window box on top of a heat mat and the gro light 4 inches above the pot.
Last winter I had to prune them bc they were vining Everywhere!

 

[flowerbug]

the only things i've read that i remember about them is that to get the larger tubers you want to prevent the sides shoots from rooting so somehow you need to scrape or keep the stems from getting contact with the soil. weed barrier fabric or cardboard might work well enough.

that they are very edible greens i've not tried but someday i might. i do love to eat the tubers. they are a lot like squash.

 

[Ridgerunner]

Here is a thread Big Red had a few years back about growing sweet potatoes up north. I thought it would be a good one to link with this thread.

Sweet potato help.

Okay, here is what I have growing on the kitchen window ledge. I've read the growing directions. I've watched the planting video on PBS for growing them in Wisconsin. I've never grown them in my garden before. What do I do with the sweet potato in its current stage? How do I get the slips...

www.theeasygarden.com

Not that far back about every sweet potato sold at the grocery store was a Beauregard. That's why so many people think sweet potatoes only come in red. Several years back I made a sweet potato casserole for a church social. Many of the ladies there could not believe it was sweet potatoes since it was white. But now, with all these specialty crops showing up I don't trust the store sweet potatoes to all be Beauregard anymore.

My research has suggested that I should start them THIS WEEK, in soil.

Ducks, that should work well. The way I started them was to put them in water with the bottom half submerged. As Cat said, they are a warm weather crop. To start the sprouts they need to be warm. Since hot air rises the warmest spot may be on top of the fridge. I used a high bookshelf. If it's too cool they can rot instead of sprouting.

What's a thread without photos. This is my starting set-up on top of a bookshelf unit. A large sweet potato standing up in a coffee can.

This was them after a month. Other sprouts grew though they don't show here.

I don't like to set long vines when I set them out in the garden and I wanted several slips. These vines are about the easiest to root that I've ever seen. When the vines got long enough I'd cut them off above a leaf node, they will send out a bud and keep growing. I'd cut them into pieces maybe a foot long, strip off the bottom leaves, and stick that back in the water. They'd soon root so you had another slip.

Several times in the garden if one died I'd cut the end of a vine that was growing and stick that in the ground. If you kept the ground damp it would grow and produce. I had a pretty long growing season in Arkansas, that may not work real well further north as far as production.

I think I grew half of the varieties Steele sells. Steele always treated me well. With a long growing season getting large tubers wasn't a problem. It wasn't a goal either. My wife did not like the really big ones, too hard for her to peel and took a long time to bake. Georgia Jets consistently made the largest tubers of any I grew. The Beauregards were plenty big enough but more consistently sized. Probably why the commercial guys used them so much.

 

[flowerbug]

i've never peeled a sweet potato in my life. scrub to make sure it is clean and then microwave until done and eat the insides and will also eat the skins too if in decent condition.

 

[Zeedman]

DW & I grew sweet potatoes for several years, but it was a variety bred for its edible shoots. It was very much like the water spinach that we love & is prepared the same... which is not surprising since they are closely related members of the Morning Glory family. The SP greens are stronger flavored though, so not for everyone. The taste of the greens varies widely between varieties too; we tried an ornamental variety, and it was horrible.

We were growing for greens not tubers, but I was curious & wanted to see if any tubers were large enough to eat. So at season's end, I started digging. That turned out to be a bigger task than expected, because the tubers were anywhere within a 3' radius of the plant, and about 12" deep, lodged tightly into the rocks & sub-soil. I had to follow the large roots from the plant to find them. Some were good sized (about 6" X 2") and I wanted to save one for next year's slips; but despite my best efforts, I couldn't dig one out without breaking it. The deep excavation was damaging the garden too, so I gave up after two plants.

Those tubers were long, twisted, white, and VERY dry when steamed. We liked them, and would grow SP for roots - if the variety forms potatoes directly under plant, where they can be easily located. I had intended to order slips from Sandhill Preservation (which has a huge heirloom SP collection) but already have too many projects taking up garden space this year.

Asian Garden 2 Table has a lot of great gardening videos on YT, one of those shows them trellising sweet potato vines. While their intent is to harvest the shoots, that might save space, and prevent the vines from rooting along their length:
Growing sweet potato on trellis

 

[catjac1975]

DD grew last year's slips...with a sweet potato in her vegetable bin!
I have my last year's harvest, about a dozen smallish and skinny sweet potatoes. My research has suggested that I should start them THIS WEEK, in soil.
As soon as the sweet peppers move on to pots on top of the fridge, the sweet potatoes will be able to occupy my 4 ft long and 8 inch deep plastic window box, with lots of rotted compost from the Last sweet potato outside potting, and I will let them grow their slips and vine down my growing shelving unit. They won't go out until June, but should do well with the window box on top of a heat mat and the gro light 4 inches above the pot.
Last winter I had to prune them bc they were vining Everywhere!

I don't know.Depending on your climate. I put them out in early June with the soil preheated. And I harden off the slips when I get them before planting. A real cold night can damage them. At that stage the slips are very tender. And the cold even above freezing could be damaging.

 

[Ridgerunner]

I started digging. That turned out to be a bigger task than expected, because the tubers were anywhere within a 3' radius of the plant, and about 12" deep, lodged tightly into the rocks & sub-soil. I had to follow the large roots from the plant to find them. Some were good sized (about 6" X 2") and I wanted to save one for next year's slips; but despite my best efforts, I couldn't dig one out without breaking it. The deep excavation was damaging the garden too, so I gave up after two plants.

The way I do mine is to hill up a row 12" to maybe 18" tall of loose dirt and plant them in that. The hill will settle some but not totally. Supposedly the hill will warm up faster than flat soil but digging them is why I do it. A couple of times early on I'll rake up loose soil on those hills when I weed them, usually a tiller in between rows and use a hoe to pull the dirt up so the hills get rebuilt. The majority of the tubers form right at the plant but I've chased down some of those roots too. I agree those can be a pain. After the plants start growing they get really thick and self-mulch but I usually have to weed/hoe them a couple of times before that happens. They can grow potatoes wherever a leaf node touches the soil and develops roots. Sometimes those aren't worth digging, sometimes they can be really nice. All this is easier if the soil is not rocky.

Because the vines spread so much I do not plant them in long rows. I generally do 3 rows, maybe 3-1/2 feet apart and 7' long, and leave about 5 or 6 feet clear all around them. I still have to turn the vines back to keep them from taking over even more. I space the slips about 9" apart in the rows. In a colder climate you may want them further apart so you might get bigger tubers. Not sure how that works for sweet potatoes but it does for a lot of things.

 

[catjac1975]

The way I do mine is to hill up a row 12" to maybe 18" tall of loose dirt and plant them in that. The hill will settle some but not totally. Supposedly the hill will warm up faster than flat soil but digging them is why I do it. A couple of times early on I'll rake up loose soil on those hills when I weed them, usually a tiller in between rows and use a hoe to pull the dirt up so the hills get rebuilt. The majority of the tubers form right at the plant but I've chased down some of those roots too. I agree those can be a pain. After the plants start growing they get really thick and self-mulch but I usually have to weed/hoe them a couple of times before that happens. They can grow potatoes wherever a leaf node touches the soil and develops roots. Sometimes those aren't worth digging, sometimes they can be really nice. All this is easier if the soil is not rocky.

Because the vines spread so much I do not plant them in long rows. I generally do 3 rows, maybe 3-1/2 feet apart and 7' long, and leave about 5 or 6 feet clear all around them. I still have to turn the vines back to keep them from taking over even more. I space the slips about 9" apart in the rows. In a colder climate you may want them further apart so you might get bigger tubers. Not sure how that works for sweet potatoes but it does for a lot of things.

Oh yea they love the heat.

 

[catjac1975]

DW & I grew sweet potatoes for several years, but it was a variety bred for its edible shoots. It was very much like the water spinach that we love & is prepared the same... which is not surprising since they are closely related members of the Morning Glory family. The SP greens are stronger flavored though, so not for everyone. The taste of the greens varies widely between varieties too; we tried an ornamental variety, and it was horrible.

We were growing for greens not tubers, but I was curious & wanted to see if any tubers were large enough to eat. So at season's end, I started digging. That turned out to be a bigger task than expected, because the tubers were anywhere within a 3' radius of the plant, and about 12" deep, lodged tightly into the rocks & sub-soil. I had to follow the large roots from the plant to find them. Some were good sized (about 6" X 2") and I wanted to save one for next year's slips; but despite my best efforts, I couldn't dig one out without breaking it. The deep excavation was damaging the garden too, so I gave up after two plants.

Those tubers were long, twisted, white, and VERY dry when steamed. We liked them, and would grow SP for roots - if the variety forms potatoes directly under plant, where they can be easily located. I had intended to order slips from Sandhill Preservation (which has a huge heirloom SP collection) but already have too many projects taking up garden space this year.

Asian Garden 2 Table has a lot of great gardening videos on YT, one of those shows them trellising sweet potato vines. While their intent is to harvest the shoots, that might save space, and prevent the vines from rooting along their length:
Growing sweet potato on trellis

Sweets are related to morning glories? They do make lush beautiful greens. I have never seen a pest on them.