About 30 years ago I accidentally left some sweet potatoes in the basement well past their one year maximum shelf life. The potatoes were wrapped in newspaper in a relative dry environment. As I unwrapped the potatoes I found they were dehydrating and all the potatoes had put out sprouts, which, for lack of light, were pale pink or red, but were indeed, totally alive little sweet potato vines, feeding off the mother plant.
I realized these sprouts would be easy to pot off and any difficulties I once had trying to get starts to form from a potato in water, or trying to grow sprouts from a big chunk of potato in soil were over. These tough little sprouts are easy to grow, easy to plant, and easy to maintain all along their path to being set in their garden bed. Now I purposely let some potatoes sprout. It takes about year and a half before they begin putting out useful cuttings.
Sweet potatoes aren’t happy in shallow flats. I made this deep box to accommodate the new vines. Its outside dimensions are 16” x 16” x 9”. Inside dimensions are about 14.5” x 14.5” x 8”. The box has drainage holes. I line the box with newsprint and fill it about 2/3 full with my very clayey garden compost. I fill the remaining 2 1/2” with commercial potting soil. The composted soil has too much weed seed to want it on top, but it will give the roots of the sprouted plants lots more nutrition than they would get from the potting soil alone. Of course, it is close to free.
I soak the soil surface until it’s wet at least 2” down and arrange 25 spouts in an equal 5 x 5 pattern in the damp soil.
I’ve placed the box next to a south facing patio door. To give it extra warmth (sweet potatoes want it hot), I’ve covered the box with a recycled plastic bag. The bag will help capture the sun’s heat and hold it in. The sprouts will soon turn green and put out more leaf and deep roots. Next, the spouts will be temporarily transplanted to the hoop tunnel where they will continue to grow until late May, when they be moved to their permanent bed.