67-year-old Elizabeth Jeacock pleaded guilty to unlawfully wounding David Jeacock when she appeared at Lincoln Crown Court.
The offence happened on May 12 this year, the court was told.
Judge Simon Hirst agreed to adjourn sentence on Jeacock for the preparation of a probation report but warned her that she could still face custody.
The judge told Jeacock: "You have pleaded guilty to a serious charge, and I don't know yet what I will do with you.
"It is absolutely a sentence of imprisonment, the issue is whether it can be suspended or not.
"I am adjourning the case until 16 December so I can know more about you.
"You still may receive a sentence of immediate custody."
Jeacock, of West End Crescent, Spilsby, was granted bail until 16 December when she will be sentenced at Lincoln Crown Court.