Police say the child ended up with the drugs when her mother gave her another backpack after hers was ruined by a family pet.
On Monday, teachers at Hickory Tree Child Care Centre found several of the children with the packets and collected them, assistant director Tamicka Goodman said.
"They found it right when she passed it out," according to Goodman. "So we do thank God that he had a watchful eye and most of all we thank God that none of the children are injured."
In addition to the 4-year-old, the woman also has a 9- year-old son and an 11-year-old daughter.
Tull is under court order not to contact her children who are staying with a relative. She was released on USD 6,000 bond.