Are Sweet Potatoes Yams?

The Great Yam Scam: What Are Sweet Potatoes?

November 14, 2018
Yam or sweet potato?

Are sweet potatoes the same as yams? No… and yes. Here’s the scoop.

Are Sweet Potatoes Yams?

Literally and botanically speaking, the two are not related.

What are yams

  • Yams are big tuberous roots that are a monocot (a plant having one embryonic seed leaf) and belong to the genus Dioscorea.
  • Yams are related to grasses and lilies, growing in tropical and subtropical countries that provide eight to ten months of warm weather to mature.
  • Yams can grow two to three feet long and some can weigh as much as 80 pounds.
  • According to horticulturist U. P. Hedrick, the word yam means “to eat” in the dialect of Guinea.

What are sweet potatoes?

  • Sweet potatoes are a dicot (a plant having two embryonic seed leaves) and are from the Convolvulacea or morning glory family.
  • In the United States today it is possible to find true yams in some urban Hispanic markets. However, most yams in the U.S. are actually sweet potatoes, and have a relatively moist texture and orange-colored flesh. Compared to sweet potatoes, yams are starchier and drier, whereas sweet potatoes are typically sweeter.

The Great Yam Scam: Types of Sweet Potatoes

Both the yam and the sweet potato DO grow underground and have yellowish-orange flesh, but there the similarity ends. Yet the two became entwined in this country by household vernacular in part through the work of a publicity campaign. Earlier this century, sweet potato promoters attached the word yam to the deep orange, moist-fleshed varieties of sweet potatoes and left the words sweet potato to the smaller, yellowish, and drier-fleshed varieties.

The two types of sweet potato are interchangeable in cooking, but bring different tastes, textures, and colors to your plate. Centennial and Puerto Rico are two popular moist-fleshed (formerly called yam) varieties; Nemagold, New Jersey Orange, and Nugget have the lighter and drier (sweet potato) flesh.

Today it is common to find either or both words used in supermarkets, although sweet potato promoters wish we would all stop saying yam. The North Carolina SweetPotato Commission currently urges the world to spell “sweetpotato” as one word. But it’s an uphill battle. If your Mama called them yams, for certain you will, too.

Trying to grow sweet potatoes? Check out our Sweet Potato Growing Guide for tips!


Reader Comments

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Sweet potatoes

In the 1970s and 80s I showed my city kids how to grow sweet potato vines indoors in water. They we're amazed how the vines trailed. Growing sweet potatoes is a rewarding, educational, and beautiful lessons for children to experience.

Yams vs. Sweet Potatoes

First, neither one is a "potato"....sweet potatoes are from the Morning Glory family while yams are from the grasses and palms family (hence the rough, dark, bark-like skin). A yam has a darker skin that is rough and almost hairy and is almost cylindrical in shape. A sweet potato has tapered ends with a lighter more delicate skin and either one can have different colored flesh.
Yams are starchy, dry, take longer to cook and need more butter (milk, cream, etc.) to make them more palatable.
Sweet potatoes on the other hand are, well....just sweeter, naturally softer, much moister and easier to prepare.
In the end, yams and sweet potato are interchangeable labels thanks to a marketing campaign in the 1930's. It also doesn't help that the FDA has no standard of identity for either one and in supermarkets you will see yam and sweet potato labels interchanged.
Hope this helps.

sweet potato vs. Yam

informative read but disappointing cause.....I STILL can't tell the diff. when I go to the store. I suspect they use the two words interchangably


i like sweet potato good for heath and to eat

SweetPotato vs. yam.

Greetings and thank you for your “Sweetpotato” information. I spent 20 years trying to explain and prove to our Office Staff we were not eating Yams. I never really succeeded. That was in the 70s & 80s. I will try finding a few Friends ,to supply them with a copy of your blog. It may help, though being an implanted Yankee , they will not be sure we are correct.
I love The Old Farmers Almanac. Remembering reading it as a child. Gail

I have read a couple of the

I have read a couple of the blog posts on your wietbse since yesterday, and I truly like your way of blogging. I bookmarked it to my bookmark web site list and will be checking back soon. Please visit my site also and let me know your opinion. -3Was this answer helpful?

when is time to dig sweet

when is time to dig sweet potatoes that was planted this pass april 13th.the kind was beaurgard

Hi Colon, the variety you

The Editors's picture

Hi Colon, the variety you planted is 100 days to harvest, so you should be able to count from when you planted to get an accurate harvest date. Otherwise, you can dig up some of the young potatoes now if you wish, but wait to harvest the full crop until just before the first fall frost in your area. Enjoy!

I planted sweetpotato vines

I planted sweetpotato vines this past summer and was surprized to fine HUGE potatoes at the end of the vines upon our first frost here in Asheville, NC. I tried one out in the oven and it was to funky to eat. I did not fertilize the vine at all and the soil is semi-soft. Are these edible? If so, what type of fertilizer is best other than compost? I did some composing from time to time in the area.