The show began three years ago as a means to raise money to fund the college's amphitheater, which is scheduled to open later this year, said Judy Kofoet, the show coordinator.
The show capitalizes on the booming interest in gardening and landscaping by using mostly local vendors, she said.
"People can see they can get what they need right here. They don't have to leave Hagerstown," Kofoet said.
Last year's show drew 3,500 people during two days and netted $12,000 for the association. Koefet expects to do even better this weekend. Money raised from the show will still be used for the amphitheater effort, she said.
One of the most unique displays this year is sponsored by Brook Lane Health Services, which handed out pamphlets promoting the therapeutic benefits of gardening.
It was Brook Lane's first year at the show.
"It's a different kind of concept for us," said Curt Miller, Brook Lane's director of public affairs.
Darlene Weddle, a Waynesboro, Pa., resident who attended the show, agreed that gardening is a great stress reliever.
"It does relieve the tension, just digging in the dirt," she said.
Weddle compared the HJC show to one she just attended in Philadelphia.
"This beats it," she said.
A new feature this year at the show is the plant exchange. For a $1 donation, people can bring in their plants and swap them for another.
Kofoet said the planning and producing of the show is long process that takes more than 100 volunteers to pull off. Plans for next year's show will begin later this month, she said.
The show continues today from 9 a.m. to 5 p.m. Admission is $3 for adults and free for children under age 12.