You might want to check the soil temperature. The nights around here have been on the cooler side.

Did they have any eyes developing on them. I find it easier to start them indoors. This gives them a head start and you also know which tubers are viable. I had to pinch off a bud on one which I haven't yet transplanted to its final location.

They had eyes on them, however, I let them outside one night and the eye dried up. As suggested by one of the members here, I still went ahead and put them in the soil. Till now there is no sign of any growth.

Anna

I had one where the eyes took 3 weeks to start enough growth that I could see it with a magnifying glass. Now that it's potted, it will probably be a couple more weeks before I see anything above the soil.