"It takes a lot to keep it going."
Greener said she had collected all of the items over the years, often purchasing Christmas ornaments online, as well as all the furniture to display them.
"I have some incredible things here, from really precious works of art to wee things I've found over the years.
"Some of the trees have such incredible decorations on them. They're just stunning."
Greener said the most photographed tree is the one covered top to bottom in Tui cans. This year's new addition, an Anzac tree covered in around 100 hand-knitted poppies, is nipping on its heels.
Greener has moved from a temporary facility to her own building, purchased by her and her husband, in Main St.
She's spent tens of thousands of dollars on bringing the building up to standard, making sure it is compliant for fires, floods and wheelchair accessible. She's even built a ramp and installed a disabled toilet.
Greener said it was a big undertaking for a place that's only open for 6.3 per cent of the year.
"It's been a big job, but we've got lovely volunteers and really supportive businesses in the community."
Asked why she dedicates so much time and money to the grotto, Greener said it was simple. It's about "presence, not presents", she said.
"I know it's a cliche, but Christmas is a time to be with people and celebrate. If I can play a role in that with the Grotto, then I'm happy,"
"I really hope it really brightens up people's Christmas."
Granny's Christmas Grotto at 1 Main St, Marton, is open Mondays to Thursdays from 7pm-10pm until December 23. On Fridays, Saturdays and Sundays the grotto is open from 12pm-5pm. Adults $5, children $3.