The event will be held at noon on Sunday at Memorial Park in Padiham to give the town a chance to show how well loved and popular the mum of two was.
There won't be a service or any public speaking and anyone who would like to lay a tribute is asked not to include the names of Katie's children in written messages.
The flowers will be laid at the fountain monument which is situated between the two 'castles' in the park and, as access from the Greenway is closed, entrance to the park is past the cenotaph, Knight Hill House or at the bottom of Bridge Street.
Katie's body was found last Saturday in the Forest of Gisburn six days after she went missing.
The town has come together to support her family and so far have raised £17,314. To make a donation click HERE