You'd probably have to mail order them at this point. NC growers were late this year getting their slips started because of the cold winter. That's where my guy gets his. But LA growers might be out by now since they might have been able to start earlier.

I know Park Seed sells them. or at least they resell them from someone else.

They take 90 to 100 days to grow to full size. You might still have time to grow them. They might not be quite as large as they would be otherwise.

Hey!

For the record, they're REALLY easy to sprout at home. Buy yourself some toothpicks, some disposable plastic cups and a few sweet potatoes.

Slice the bottom of the sweet potato at an angle so some of the flesh on the inside is exposed. Stick a few toothpicks in it so that when you fill the cut with water half-way and submerge the potato, it doesn't sink (the toothpicks are basically holding the potato in place in the cup). Place the potato somewhere that's warm and sunny, wait a few weeks. The potato will start to grow roots and soon a shoot will protrude out the top.

:)

I grew all of my sweet potatoes from cuttings this year. They growing like weeds!