MeriClone Labs sweet potato plants
The past 2 years I have purchased sweet potato 'slips' (plants) from MeriClone Labs in California. Their plants are top notch and the prices are great. They do not have the selection that Sand Hill Preservation has but they have plants year round.
Debbie is my contact person. They take PayPal.
Here is a link that might be useful: Sweet Potato Plant Vendor