Judge Simon Darwall-Smith today passed down the sentence at Bristol crown court, telling Spry that he found it difficult to understand how she committed such crimes "with regularity and premeditation".
He added that she was guilty of "sadistic torture" and "despicable acts of violence" and said it was one of the worst cases he'd ever come across during his 40-year legal career.
During her trial, the court heard how Spry made the children in her care eat their own vomit and forced sticks down their throats.
One child was forced to use a wheelchair for a year after an accident even though she did not need one.
Spry, who claims to be a devout Jehovah's Witness, denied all the charges and said that the only physical punishment she ever used was a "smack on the bottom".
A spokesman for Gloucestershire police said the force were "very satisfied with the sentence, which reflects the gravity of the offences".
At the time of her conviction, Detective Constable Victoria Martell said that Spry had "never accepted she had done anything wrong" and was a "very cold, manipulative woman".
"Most people, when faced with the accusations she was faced with, would have shown some reaction but her lack of emotion was very chilling," DC Martell added.
One her victims described how Spry prevented him from mixing with children of his own age.
"My foster mother never showed me any love or encouragement, only negativity or abuse," he said. "She locked me up in the bedroom once with my sister for about a month."
Spry was also ordered to pay £80,000 in costs.
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