The Scottish First Minister, who has often spoken about her love of literature, said she only began keeping a diary earlier this year but now updates it almost every day.
Appearing at an event with the author Damian Barr at the Wigtown Book Festival, the SNP leader also said she would like to write a novel but was unsure if she had it in her.
Discussing the books that had influenced her life, Ms Sturgeon highlighted The Color Purple by Alice Walker as a particular influence during her teenage years.
Published in 1982, the novel tells the story of Celie, an abused and uneducated black woman struggling for empowerment in 1930s America. It won Walker the 1983 Pulitzer Prize for Fiction.
“This was a very powerful read for me,” Ms Sturgeon told the audience.
“I can still conjure up how that book made me feel, which was sad and angry, but also hopeful because there’s such a positive vibe around the human spirit in that book, and the power of friendship and love to overcome even the worst injustices in the world.”
She also listed many other books that had influenced her, from classics such as Emily Bronte’s Wuthering Heights and Jane Austen’s Pride and Prejudice to more contemporary works.
As well as 2016’s Homegoing by Yaa Gyasi, she also selected three books that were only published this year: The Mars Room by Rachel Kushner, The Quaker by Liam McIlvanney and White Houses by Amy Bloom.
Asked by Barr if she had ever kept a diary, Ms Sturgeon replied: “Not really, not as much as I should.
“I wish I had over the past decade, but I started this year and try to do it every day.”
When the author asked if she planned to published them, she replied: “Not yet,” before adding: “I’d love, love, love to think I could write a novel, but I’m not sure I’ve got it in me.”
Writing on Twitter after the event, Barr joked that the news Ms Sturgeon was writing a diary was likely to spark immediate interest among publishers, urging them to “get in now”.
The First Minister was also asked if she ever cried while reading books.
“I cry in books often, but not as much as I cry at the news sometimes,” she told the audience.
She also said she tried to read every night before bed, even for just 15 or 20 minutes, adding that as her job gave her very little time to herself, she tended to be very careful with what she had.