Answer: Potatoes can take 2-3 weeks to sprout, depending upon soil temperature. Heavy clay soils can retard their growth (and also produce unattractive tubers). If you planted in a loose sandy loam, you can expect to see shoots most any time, now. Hope you have a terrific crop.
p.s. If you're really curious, dig up one of the potatoes to see what kind of progress it's making.
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