WICHE: Sweet potatoes yield a bumper crop

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By Jeneen Wiche

We are still eating from a fantastic harvest of sweet potatoes last fall.  I planted out about 25 organic slips purchased from Country Corner Greenhouse in Shepherdsville in late May, and by early November we had 4 nursery crates full of one of nature’s perfect foods! 

Seven months and counting in storage with no spoilage is impressive, but now we are down to about six sweet potatoes – just in time for a transition to other summer vegetable. 

Up until last week it has been too cold for sweet potatoes; this southern crop is tropical by nature but can be grown successfully in Kentuckiana as long as we wait until it is warm, with nighttime temperatures in the 60’s.

As long as they have 150 frost-free days and some steamy Ohio Valley weather, we will be knee deep in sweet potatoes by Thanksgiving again.  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 takes me about 10 minutes to prep the row with come composted manure and a garden fork, and another 10 minutes to pop two dozen slips into the ground. They are watered in with a little fish emulsion and generally perk back up the following day, but if it is hot I will shade them until they root out. 

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 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 and irrigate when necessary – sweet potatoes will really plump up with adequate moisture – and wait. 

Many sweet potato growers suggest fertilizing only a portion of your plants. So you be the judge – the general consensus is that unfertilized sweet potatoes taste better.  Let your compost do the work instead!

Sweet potatoes are harvested after the first fall frost turns the foliage black. 

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 two weeks – dirt and all – before you put them in storage. Prior to 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.  I noticed last year it took about a month in storage before the sweetness really came forward.

Properly cured sweet potatoes can store for six months or more at about 50 degrees.  Obviously our slightly warmer basement was adequate since we are going on seven months of successful storage. 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.

Store-bought sweet potatoes are on the move, 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.