WICHE: Sweet potatoes need 150 days

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Some tips for growing sweet tubers

By Jeneen Wiche

I was in Shepherdsville at Country Corner Greenhouse earlier in the week and picked up some good-looking sweet potato slips that are finally ready for the garden. Up until last week it has been too cold for this southern crop.

Sweet potatoes are tropical by nature but can be grown successfully in Kentuckiana as long as we wait until it is warm (nighttime temperatures in the 60’s). As long as they have 150 frost free days and some steamy Ohio Valley weather we should knee deep in sweet potatoes by Thanksgiving. Homegrown sweet potatoes are far superior to anything you would find at the grocery so if you love this crop as much as I do you might consider planting a plot.

Sweet potatoes require very little attention – other than keeping the weed competition down. It took me about five minutes to prep the row with come composted manure and a garden fork and another few minutes to pop the dozen slips into the ground. They were watered in with a little fish emulsion and should perked up the following day beneath a shower of soft rain. It was perfect timing, for once.

Ideally the bed should be a little on the sandy side so that drainage is maximized but average garden soil amended with composted manure is adequate.

Unlike the potato, which is planted out in tuber form, the sweet potato is planted out as little seedlings called slips. You can grow your own slips by cutting a sweet potato into several chunks, suspending them on tooth picks in a bowl and covering half the tuber with water; sprouts will form and these are “harvested” as your slips for planting.

Plant your slips in mounds about 12 inches apart. Sink the slip so that the top leaves are just sticking above the soil surface. Water in (and irrigate when necessary, sweet potatoes will really plump up with adequate moisture) and wait.

Many sweet potatoes growers suggest fertilizing only a portion of your plants so you can be the judge. The general consensus is that unfertilized sweet potatoes taste better.

Sweet potatoes are harvested after the first fall frost turns black the foliage. Carefully dig your sweet potatoes with a garden fork and let them dry in the sun for a couple of hours and then transfer them to a warm, shaded, well-ventilated area and spread them out on some screens or newspaper. Let them cure in the warm shade for another 2 weeks, dirt and all before you put them in storage. Before storage use your hands to rub off residual dirt but do not wash them.

You can harvest “baby bakers” as they grow, but the sweetness of the potato is enhanced if you wait until after frost and several weeks of curing. This process allows the starches to turn to sugar.

Properly cured sweet potatoes can store for 6 months or more at about 50 degrees. I told my husband I want him to dig me a root cellar for Christmas this year. I plan on a bountiful harvest.

But if this wish does not come true, a cool corner of the basement will have to do.

Some old-time sweet potato growers are emphatic about not disturbing your sweet potatoes until you are ready to eat them. This is why, they say, homegrown sweet potatoes are better than store-bought, too.

Store-bought sweet potatoes see a lot of movement, which causes the sugars to constantly move through the tuber, hastening undetectable spoilage. The homegrown variety sits quietly which allows the sugars to settle to the bottom, keeping the tuber fresher and sweeter.

If you decide to grow sweet potatoes annually, then be sure to rotate the crop to control potential insect problems. There are few pests, really, but if you plant in the same place year after year, the sweet potato weevil may find itself a permanent home.


Check out gardening columnist Jeneen Wiche’s work at www.SwallowRailFarm.com. You can find her columns also at www.SentinelNews.com/agriculture. She answers questions once a month in SentinelNewsPlus. To submit a question, send an E-mail to jwiche@shelbybb.netand type “Sentinel-News” in the subject field.