It’s spring and many are excited about planting a garden. I love to frequent several gardening forums and note that “newbies” frequently jump the gun, planting so early that their crops will die or be severely stunted. This is true with many crops but it’s especially true of sweet potatoes. Sweet potatoes love the heat. They HATE to be chilled. A crop failure may be the result of exposure to chilly temps, even if the plants survive.
Most crops shouldn’t be touched by frost. Sweet potatoes shouldn’t even be chilled.
Sweet potatoes love the heat. They need heat. They’re tropical in origin and it shows in their needs. See our feature photo, above? That was taken on March 1, 2014, the last year I started my roots sprouting way too early. I bedded the roots on February 1, that year, spending more than I cared to think about heating, in order to get them to sprout on our sun porch. By March 1, we were months away from planting time and the slips (stems used for cuttings) were already oversize. Amazingly…
I had customers, wanting to purchase slips by the middle of March
even though it was still too cool outside for planting. We had a really hard freeze on April 15, and in another year had hard frost as late as May 7. One ought to plant their sweet potato slips when nights are warm. I interpret “warm” to mean that I can be outside, even in the wee hours of the morning, before sunrise, and be comfortable without wearing a sweater.
Glenn Drowns, of Sandhill Preservation Center, is one of my friends and sweet potato mentors. He sells hundreds of varieties and ships all over the country. Glenn often speaks of the importance of warmth for every stage of sweet potato production. His Iowa climate is much cooler than our Oklahoma climate. He has told me of putting out half a planting of a variety and then getting shut down for nearly a month, due to cool, wet conditions. A month later he planted the rest of that variety’s slips, only to discover that the slips planted a month later out produced the early planting, and that, by a long shot!
So, with sweet potatoes, plant later, rather than earlier.
Here in Oklahoma, I’ve had a good crop from slips planted as late as the first week in July. I prefer to get my slips in before June, but if I lived further north, I’d probably wait. The key is, don’t go by date, plant by the weather. Is it consistently warm?
Sweet potatoes can be grown way farther North than most people think.
Even though sweet potatoes love heat and need it, places up North are often warm enough to produce a good crop. Glenn has told me of customers who have succeeded with sweet potatoes in Maine and in southern Manitoba!
Some tips for growing sweet potatoes in cooler locations:
- Don’t plant too early if temps are still cool. You won’t gain anything by it and might lose your crop.
- Use black plastic mulch to increase your soil temperatures and help those heat-loving sweet potatoes to thrive.
- Plant varieties are known for being “early.” An early sweet potato variety produces sizable roots more quickly than a late or mid-season variety.
- No matter what, dig your sweet potatoes before nighttime temperatures get very chilly. If the soil cools, the roots can be damaged. Dig them while it’s still warm.
No matter where you live, store your sweet potato crop in a warm location.
Temperatures below 55 °F (13 °C). can cause roots to spoil more rapidly. I get the best results by stacking my boxes of roots in the same room as our wood stove.