Sweet potatoes and yams are often used interchangeably, causing confusion in the kitchen and grocery store. But are they really the same thing? Let’s explore the key differences and similarities between these two root vegetables.
Will Kornegay, formerly of Ham Farms and now CEO of Ripe Revival, has extensive knowledge of sweet potatoes. He helped to clear up the confusion surrounding yams and sweet potatoes.
Yams vs. Sweet Potatoes: Untangling the Confusion
So, why do people get sweet potatoes and yams mixed up? The answer lies in marketing and history.
What is marketed in the United States as “yams” are really a variety of sweet potato, grown in the South. A true yam is a starchy edible root of the Dioscorea genus, and is generally imported to America from the Caribbean. It is rough and scaly and very low in beta carotene.
In the United States, what’s typically labeled as “yam” is actually a type of sweet potato with vibrant orange flesh and a soft, moist texture when cooked. True yams, on the other hand, are starchy tubers with rough, scaly skin and are typically imported from the Caribbean. They are also lower in beta carotene.
The confusion started when orange-fleshed sweet potatoes were introduced to the Southern United States. Farmers wanted to differentiate them from the existing white-fleshed varieties. Newcomers to America, noting similarities between these sweet potatoes and yams from their native lands, began calling them yams. The African word “nyami,” referring to a starchy, edible root, was adopted into English as “yam.”
The U.S. Department of Agriculture requires that the label “yam” always be accompanied by “sweet potato.”
Growing Regions: Where Yams and Sweet Potatoes Thrive
Yams and sweet potatoes also differ in their growing regions. Yams thrive in tropical climates, particularly in South America, Africa, and the Caribbean. Sweet potatoes, however, can be grown in regions with a long, warm, frost-free period.
Most sweet potato varieties need a minimum of 100-125 frost-free days with an average daily temperature of 77 degrees Fahrenheit. They also require about an inch of water per week throughout the growing season. These conditions are primarily found in the southern United States.
Sweet Potato Farming: A Closer Look
Sweet potatoes are primarily grown in the southern U.S. due to the favorable climate and soil conditions. They thrive in sandy, loamy soils.
Here’s a glimpse into sweet potato farming practices, based on information from Ham Farms:
- Soil Sampling: Soil is tested during the winter months to determine the proper fertilization needs for the upcoming crop.
- Certified Seed Production: Elite plants are cultivated in greenhouses and transplanted into fields. The harvested roots become seed stock for the following year, ensuring a healthy, disease-free crop.
- Bedding and Transplanting: Seed stock is bedded in early March to produce sprouts, which are then transplanted into the fields in May using precision transplanters.
- Cultivation and Weed Control: Fields are regularly cultivated to control weeds.
- Harvest Planning: Sampling begins in July to assess the crop’s condition and readiness for harvesting.
- Harvesting: Field rows are turned up to uncover the sweet potatoes, which are then hand-harvested and graded. The roots are transferred to controlled atmosphere storage facilities for curing.
- Curing: The curing process takes 4-7 days, healing cuts and reducing decay and shrinkage. It also converts starches to sugars, enhancing the sweet potato’s flavor.
Crop Rotation: Maintaining Soil Health
Sweet potato farmers often rotate their crops to maintain soil health and prevent pest and disease buildup. Common rotation crops include soybeans, wheat, cotton, cabbage, peppers, and other vegetable crops.
Determining Harvest Readiness: Sampling is Key
Determining when sweet potatoes are ready for harvest requires careful monitoring and sampling. Field testing is conducted after 90-120 days of growth, provided growing conditions have been favorable. Farm managers turn up hills to assess the crop’s condition, size profile, and overall readiness. Random sampling provides insights into each field’s characteristics and guides the harvest plan.
Culinary Delights: Enjoying Sweet Potatoes
Sweet potatoes are incredibly versatile in the kitchen. They can be baked, mashed, roasted, fried, or grilled. Will Kornegay enjoys them cut up and grilled as fries.
Beyond the Basics: Exploring Sweet Potato Varieties
There are many varieties of sweet potatoes. They are smooth with skins that can vary in color, depending on the variety, from pale yellow to deep purple to vivid orange. Flesh colors can range from light yellow to pink, red, purple or orange.
Conclusion: Embracing the Sweet Potato
While true yams and sweet potatoes are distinct vegetables, the term “yam” is often used to refer to certain varieties of sweet potatoes in the United States. Understanding the differences in appearance, texture, and growing regions can help you make informed choices in the grocery store and expand your culinary horizons. So, whether you’re enjoying sweet potato fries or a baked sweet potato, embrace the versatility and nutritional benefits of this delicious root vegetable.
