Sweet potatoes can be grown where there is a long frost-free period with warm temperatures in the growing season. Most cultivars require a minimum frost-free period of 100-125 days, with a minimum average daily temperature of 77 degrees. Sweet potatoes also require almost an inch of water per week uniformly distributed throughout the growing season for highest yields. Conditions 6 to 7 weeks after planting are particularly critical to development or “set” of storage roots. If soil oxygen is low, either because the soil is flooded or because it is so dry a crust has “sealed” the soil, the storage roots do not set well and yields are reduced.