A cheque for $110,000 (£70,000) from Lemony Snicket creator Daniel Handler will be winging its way towards America’s campaign for diversity in children’s books on Monday in recompense for remarks the author has now admitted were racist.

The bestselling writer, hosting the National Book Awards in the US on Wednesday, made what he initially described as “ill-conceived attempts at humour” when presenting black American writer Jacqueline Woodson with the prize for young people’s literature for Brown Girl Dreaming. The book is Woodson’s story of her childhood as an African American in the 1960s and 70s, told in verse.

“I said that if she won I would tell all of you something I learned about her this summer. Jackie Woodson is allergic to watermelon. Just let that sink in your minds,” Handler said last Wednesday. “I said, ‘You have to put that in a book.’ And she said, ‘You put that in a book.’ And I said, ‘I’m only writing a book about a black girl who’s allergic to watermelon if you, Cornel West, Toni Morrison and Barack Obama say, ‘This guy’s OK.’”

He was heavily criticised for the comments, and last Thursday issued an initial apology on Twitter, saying: “My job at last night’s National Book Awards #NBAwards was to shine a light on tremendous writers, including Jacqueline Woodson and not to overshadow their achievements with my own ill-conceived attempts at humor. I clearly failed, and I’m sorry.”

He has now followed this up with further apologies, describing the remarks as “monstrously inappropriate and yes, racist”.

“It would be heartbreaking for the #NBAwards conversation to focus on my behaviour instead of great books,” Handler wrote on Twitter. “So can we do this? Let’s donate to #WeNeedDiverseBooks to #CelebrateJackie. I’m in for $10,000, and matching your money for 24 hours up to $100,000. Brown Girl Dreaming is an amazing novel and we need more voices like Jacqueline Woodson.”

Donations poured in, and Handler has now confirmed that he will be sending the We Need Diverse Books campaign a cheque for $110,000. The diversity project was set up earlier this year by a group of authors and publishers in the US, in reaction to the paucity of children’s literature published with non-white protagonists. It is backed by authors in America including John Green, and writers in the UK including Malorie Blackman and Patrick Ness. Woodson herself is an advisory board member.

“Daniel Handler has confirmed he’ll be sending a cheque for $110,000 on Monday,” said the We Need Diverse Books team. “Thank you all so much for spreading the word and donating (and donating again)! We believe so much in our mission to celebrate diversity and diverse artists in publishing and glad you believe in it too.”

The campaigners intend to use the money for establishing internships for “people from diverse backgrounds in an effort to diversify the publishing industry behind the scenes”, citing a report from Publishers Weekly which found that of 630 publishers who identified their race in a recent survey, “89% described themselves as white/Caucasian, with 3% selecting Asian and another 3% indicating Hispanic. Only 1% said they are African American”.

There are also plans to create educational kits for schools and libraries, to launch the inaugural “Kidlit Diversity festival” in 2016, and to provide travel grants for authors to attend conferences and events.