She will be at the centre from 10am to 4pm and will be hosting two gardening talks including one on planting up containers and hanging baskets as well as offering advice to visitors.
The former Ground Force star was recently on TV in The Great British Garden Revival. She will be promoting Westland at the event.
Centre manager Steve Nicholls said: "‘We’re delighted to have Charlie join us for the day. As a well-known and popular gardening expert, her extensive knowledge will be a real treat for our regular visitors.’
Newbridge Nurseries became the 17th Blue Diamond Group centre in January 2015.