Wait a few months. Sweet potatoes are very easy to grow, but they take a long time. I usually dig them up just before the first frost, in October or November. I guess you could grow them year round in zone 10, since sweet potatoes are perennial.

Imo, sweet potatoes are one of the very best plants to grow. In addition to being delicious, low-maintenance and nice to look at, they produce more food (measured in calories) per unit of land than almost any crop. The leaves are also nutritious.

Note that sweet potatoes ARE roots. They will size up as the season goes on. If you set them in May, don't look for much until the end of September.

I set mine out in mid-May or so. I stuck my fingers in the ridge and hit a nice sized "root". So, who knows? I have found that my sweetpotatoes usually have some pretty good sized ones by August.

I would imagine I'd have at least some root swelling by now. When I planted them I stuck the slips vertically in the ground and buried 5-6 inches of the stem. Does that mean that maybe the poatoes are way down deep? It's also raining a lot could that make a difference.

They might be way down deep, but mine start at ground level...top of ridge. I had about 15 inches of rain in a 30 day period and if they are in a ridge, they will still be ok.