Gordon Johnson, Extension Vegetable & Fruit Specialist; gcjohn@udel.edu
Sweet potatoes are planted from the end of May through the middle of June in our region. Commonly production is on ridges in conventionally tilled soil. I was recently asked about the potential to plant sweet potatoes using plasticulture (plastic mulch and drip irrigation). While not common in our region because of the cost, this has been a practice used further north where season extension is needed for production.
Lay 4’ black plastic mulch with 3’ bed top, and on 6’ centers. On each bed, two rows can be planted with 9-12” between plants in the row and 18-24 inches between rows. Waterwheel transplanters can be used but it is important to get several nodes in the ground as crews place the slips. Plant at depth of 3 inches with no less than 2 plant nodes in the ground and leaving at least 2 leaves or more above the ground. This is often difficult to do while riding the transplanter and it may be necessary to create the holes with the waterwheel and then go back and hand set the plants at the proper depth.
At the end of the season, for mechanical digging it will be necessary to mow the tops and then remove the plastic. Sweet potato yields in plasticulture have been excellent in our region – similar to or better than bare ground.