Improving the yield and quality of sweet potatoes grown in New York
In the last 5 years, the number of farmers markets in NY has nearly doubled. Many of these markets are “winter” markets”. These winter markets represent two things: First, the desire of consumers wanting to continue purchasing locally grown, fresh produce and support local growers. Second, it represents growers trying to extend their marketing season and improve their overall profitability. Growers attending these winter markets are looking to provide their customers with a diversity of products above and beyond the standard storage crops such as potatoes and carrots. Many of them have adopted high tunnel production methods in order to be able to provide greens such as spinach and leaf lettuce during the early winter months. However, many of them have also tried producing sweet potatoes with some success.
Most sweet potatoes are produced in southern states such as Louisiana, Tennessee and the Carolinas due to their long growing season requirements; although we know they can be grown here in NY and New England with some modifications. However, not much information is available for growers on producing sweet potatoes in more northern climates. Therefore the object of this project is to conduct several on-farm trials to determine proper variety selection, environmental modifications (plastic mulch, row covers etc.), spacing comparisons and the use of transplants instead of the traditional slips (cuttings from production beds produced in the south and shipped to growers in early spring). Not only is this project to conduct on-farm research, but to pull together information from many growers already producing sweet potatoes have experimented on their own.
Performance target – This project will improve quality and production of sweet potatoes on 8 of the 10 farms participating in the project. Fifty additional growers will attend workshops and meetings and twenty of them will add sweet potatoes to their operations, helping diversify the industry and provide a nutritious commodity seldom produced locally in the Northeast.
Due to funding issues, we were only able to conduct one on-farm research trial at Samascott Orchards. We were also able to provide 2 other growers with a between 15 – 20 slips of 3 varieties being evaluated in the research trial for their observation.
Additionally, we were able to make a key contact with Scott Farms, in North Carolina, a major supplier of sweet potato slips to growers in New York. They were very interested in our work and supplied us with all of the sweet potatoes for this trial.
In 2010, one on-farm research project was conducted at Samascott Orchards in Kinderhook, NY. The trial evaluated 6 different varieties on two different types of plastic mulch (traditional black and infrared transmitting or IRT mulch). We also evaluated plant spacing; single row at 15” versus a double staggered row at 18” to determine the effects on root uniformity and yield. We also compared the use of transplants to bare slips to observe differences in earliness, yield and root quality. The entire research trial was planted on June 4, 2010 and harvested on September 30, 2010. In all cases, plants were planted into raised beds on 6.5’ centers with single rows of plants spaced at a 15” in-row spacing. The exception to this was the spacing trial. Roots were cured and stored until November 23, 2010 when they were graded, counted and weighed.
Variety Trial: The following varieties were evaluated: Covington, O’Henry, Beauregard, Centennial, Georgia Jet and Carolina Ruby. Data is still being analyzed. We hope to obtain several experimental lines this year from the University of North Carolina’s breeding program.
Plastic Mulch Study: This trial was designed to evaluate any differences in yield and quality between traditional black plastic mulch and IRT or infrared transmitting mulch. The growing season of 2010 was one of the hottest and driest on record in eastern NY. Therefore, no differences were observed between the two types of mulches.
Slips versus Transplants: This was a non-replicated trial due to the fact that we were not able to obtain our slips early enough to transplant them into plug trays and grow them out. Therefore we worked with a limited number of transplants that were started by Jim Ballerstein at the New York Agricultural Experiment Station. We found that although slips produced the greatest total marketable root yields, transplanted plants resulted in larger average size jumbo and large roots. Transplants also resulted in the fewest small roots. Implications of this data could mean that transplanted plants may produce larger roots earlier in the season. This means growers could harvest some percentage of their crop for earlier markets.
Spacing Trial: Plants were either planted at the most common spacing we find in the Northeast which is 15” in row. We compared this with a double staggered row with a in-row spacing of 18”. Using the double staggered rows resulted in fewer jumbo roots, but more large and small roots overall compared to the single row. Single row spacing resulted in the greatest number and slightly larger jumbo roots. Further evaluation of spacing is needed with the possibility of including 1 or 2 more spacing options.
Impacts and Contributions/Outcomes
At a twilight meeting held on October 22, 2010 entitled “Growing for Winter Markets: Crops that can extend your season” at the Barber Farm in Schoharie County, we displayed representative samples of all six varieties that we trialed during the season and discussed our trial results to 25 growers in attendance. Many growers are still surprised that we can even grow sweet potatoes in our climate and are very interested in learning more. I have received several phone calls from interested growers wanting sweet potato cultural and variety information as a result of the above mentioned meeting. I will be presenting this information as well as displaying the six varieties again on February 15, 2011 at the Capital District Vegetable and Small Fruit Growers Winter Meeting.
Based on our findings, Samascott Orchards has chosen to grow the variety Covington for a majority of their 6 acres of sweet potatoes. They were very impressed with the yield and quality of this variety. Typically they have chosen to grow four different varieties which have made it difficult to keep track of.
Cornell Cooperative Extension Capital District Vegetable & Small Fruit Program
415 Lower Main Street
Hudson Falls, NY 12839
Office Phone: 5187462562
Stanton’s Feura Farm
210 Onesquethaw Creek Road
Feura Bush, NY 12067
Office Phone: 5187682344
Cornell Universtiy NYSAES
NYSAES – Hedrick Hall
630 W. North St.
Geneva, NY 14456
Office Phone: 3157872213
585 Meeting House Road
Valley Falls, NY 12185
Office Phone: 5186923188
New York State Agricultural Experiment Station, Cornell University
NYSAES – Hedrick Hall
630 W. North St.
Geneva, NY 14456
Office Phone: 3157872223