growers know
“ The orange-fleshed sweet potatoes are one of the best natural sources for vitamin A — half a kilo is likely to have four times the recommended daily requirement .”
Sweet Potato Trials
The Helen Keller Institute ( HKI ), based in New York City , made a request to ISH to produce sweet potatoes as a substitute for Irish potatoes . This was because the vitamin A in the sweet potato could reduce childhood blindness associated with malnutrition . The ISH planted two types of sweet potato : an orangefleshed Beauregard from commercial plant starts and a local heirloom variety provided by a neighbor . Even though the Beauregard were attacked by insects , likely Japanese beetle , the plants produced about five kg / m 2 . The local variety suffered no insect attack and produced nine kg / m 2 . Both varieties were harvested at 120 days growth . Similar trials in Colombia produced 12 kg / m 2 in 95 days . Those conducted in Bangladesh produced four to five kg / m 2 in 120 days despite being attacked by insects . Most of these trials , on average , were higher producing than soil-based sweet potato crops . Globally , the Food and Agriculture Organization of the United Nations found the average production of this tuber in soil to be 14 tons per hectare , or 1.4 kg / m 2 , although there are reports as high as 45-60 tons per hectare , or 4.5 to 6 kg / m 2 , in Israel .
128 grow cycle