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Contact Us

Nathan Johanning
Extension Educator, Local Food Systems and Small Farms
University of Illinois Extension
402 Ava Rd.
Murphysboro, IL 62966
Phone: 618-687-1727
FAX: 618-687-1612
njohann@illinois.edu

Vegetable Production

Vegetable Production

General

Sweetpotato Production

Locally grown sweetpotatoes are popular produce items at farmer’s markets and other similar markets in the lower Midwest. Sweetpotatoes are an excellent crop to include in local market venues during the fall months as consumers identify with their uses during the fall and early winter holiday seasons. The sweetpotato (Ipomea batatas) is a member of the morningglory family (Convolvulaceae) and produces an elongated root with tapered ends having smooth, thin skin. They provide several nutritional and other benefits:


1) Low amount of calories as well as many significant health benefits.                     Sweetpotatoes are fat-free, cholesterol-free, and provide high amounts of vitamins A, B-6, and E. An averaged-sized medium sweetpotato is low in sodium and only contributes about 140 calories to a diet.
2) High amounts of iron and potassium along with many other important vitamins and minerals.
3) An excellent source of dietary fiber, which lowers the risk for colon and rectal cancer, heart disease, diabetes and obesity.
4) Antioxidants, such as beta-carotene, that provide protection against heart disease, stroke, cancer, and delaying the progression of Alzheimer’s disease.


The sweetpotato is one of the easiest vegetables to grow in the lower Midwest due to the lack of significant disease and insect pest problems, as well as their ability to effectively scavenge nutrients from the soil. It is also a good competitor with weeds, as sweetpotato plants tend to form a vine-like growth over the soil surface suppressing weed growth. Sweetpotatoes are highly adaptable to sustainable production or organic systems due to the low inputs required, as adequate crops can be produced with little added fertilizers or pesticides. The crop has the potential to provide lower Midwest growers substantial returns on small investments, since few off-farm inputs are required to produce the crop. There is great potential to add this easily grown, highly sustainable crop to local direct marketing systems. Although consumer demand for this crop is high during the late fall and early-winter holiday season, many consumers do not know (especially younger consumers) how to prepare sweetpotatoes. Research has indicated that sweetpotato sales in local markets would increase if the product was marketed along with recipes and/or samples of sweetpotato foods.

PRODUCTION TIPS FOR SWEETPOTATOES:

1) Transplant production
         a. Sweetpotatoes are vegetatively propagated by transplants (or slips) produced from              previous years roots.
                    i. The primary cultivar grown is ‘Beauregard’ due to its high quality roots and                                yields, as well as short growing period (90 days). Other cultivars grown                                      include ‘Hernandez’ and ‘Covington’.
                    ii. Roots that are bedded can be saved from previous years crops or                                             purchased from seed sources in Louisiana or North Carolina
                    iii.Small- to medium-sized roots placed in beds and covered with soil in early                                  spring
                    iv. Plants can be pulled continually once they reach ~ 6 to 8 leaves for about 4                               to 6 weeks
                     v. Transplants can also be purchased from growers in Louisiana or North                                       Carolina
2) Planting of sweetpotatoes
          a. Form raised beds (about 8 inches high and 3 feet wide) on about 6 ft centers
          b. Best to plant before mid- to late-June in lower Midwest
          c. Transplants (slips) should be planted three to four nodes deep (3 to 4 inches deep)
          d. Plant about 12 inches apart in the row, increase percentage of number one roots                         by planting 2 rows per bed with about 9 inches between offset rows
          e. Most use vegetable transplanter
          f. Generally, need about 10,000 plants per acre
          g. Use well-drained field soils (as sweetpotatoes do not like waterlogged conditions)                         and avoid planting into a field that was previously in sod as this increases the                             likelihood of white grub and wireworm problems
3) Fertilization
          a. Apply about 30 to 50 lbs N per acre at 30 days after transplanting
          b. Excessive nitrogen will result in excessive vine growth, with few sweetpotato roots                       produced
4) Irrigation
          a. Greatest moisture needs in August into September when roots are rapidly growing                    (apply about 1” of water per week), otherwise somewhat drought tolerant
          b. Moisture stress during root enlargement will reduce yields
5) Pesticide applications
          a. Insect, disease, and weed control information can be found in the Midwest                                   Vegetable Production Guide for Commercial Growers 2013                                                                     http://www.btny.purdue.edu/pubs/id/id-56/195_SweetPotato.pdf
6) Harvesting, curing, and storage
          a. Check several plants in field to make sure roots are optimal size
                    i. Most sweetpotato varieties are ready to harvest anywhere from 90 to 120                                 days after transplanting (harvest date is dependent on cultivar)
                    ii. Mow vines 2 to 3 days before digging to toughen skin as this helps to reduce                            skinning of sweetpotatoes
                    iii. For digging of roots, most smaller growers will use a three-point                            middle-buster plow or a chain-driven, one-row harvester
                    iv. Handle the sweetpotatoes as little as possible to prevent bruising and                                       skinning
                    v. Do not wash the sweetpotatoes until they are ready to be marketed
         b. Curing and storage of sweetpotato roots
                    i. Place in a warm (~85º F), humid (~ 95% relative humidity) environment for                              about 1 week to increase sugar levels, and to heal cuts and bruises that                                    occurred during harvest
                    ii. Store in boxes or bins at 55º to 60º F with ~ 90% relative humidity until                                    marketing or bedding for transplant production
                    iii. Under optimal conditions, sweetpotatoes can be stored for 8 to 10 months
                    iv. Do not refrigerate sweetpotatoes

Support provided by the College of Agricultural Sciences, the Department of Plant, Soil and Agricultural Systems, and the Illinois Council on Food and Agricultural Research (C-FAR).
Published June 2007