Thongdee Jaemsri was originally sentenced to three years and four months by the Criminal Court in March, but the Appeal Court Thursday agreed to reduce her sentence.
Thongdee was found guilty of growing krathom, classified as a Type 5 drug in the same category as marijuana, at her home in the Lat Phrao area with the intent to sell.
She also installed a 200-Volt electrified fence around her home to ward off trespassers following several burglaries.
On the night of Feb 10, 2011, 20-year-old college student Maropi Langmae tried to enter Thongdee's property and was electrocuted.
Police later discovered the woman was growing 30 krathom plants, weighing about 41kg in total, around her home.
The Appeal Court said it had reduced Thongdee's jail term because Maropi was also partly to blame for trying to trespass on her land in the first place.
Thongdee will serve out her term at Klong Prem Women's Prison.
Her daughter, Juthamas Sukantachalathorn, said her mother would not be bringing the case to the Supreme Court. She would instead be seeking a royal pardon.
"Mother is very ill. She has thyroid problems and is suffering from emphysema. She doesn't want to fight the case anymore," Ms Juthamas said. "All I can do is visit her at the prison."