Morgan Jones Park Community Allotments is set to welcome visitors for an open day from 2pm to 6pm on Friday, September 27.
A number of stalls will be set up, selling plants, pot holders, knitted baby clothes and other home-made goods.
There will also be a host of activities for children, such as paper pot making and broad bean planting, among others.
Refreshments, such as tea, coffee, squash and pizza will be provided at the event, which is open to everyone.
Elizabeth Thomas, secretary of the community allotments, said the group wants to “raise the profile of community gardening”.
The site, which was cleared in 2013, now has five allotment plots, a mini orchard and an area to encourage bee-pollination
Allotment members are also looking to raise money to create a small wildlife area at the site.
Mrs Thomas said: “We’ve had a couple of open days previously, but this will be the first time we’ve had stalls.
“We chose to have the open day on this date because there won’t be any Rugby World Cup matches on.
“We’re also hoping to do future social events here around Christmas time and in the spring.
“We would also like to thank all the kind people who have donated plants, gardening items and building materials. Your support has been invaluable and we are very grateful.”
Meanwhile, a new pizza oven has been fitted on the site.
Mrs Thomas said: “The pizza oven was the work and brainchild of Keith Jones assisted by Paul Thomas, with some input from Ystrad Mynach work experience students.”
Anyone interested in setting up a stall can text 07484848491 to express their interest.
There will be space for around ten stalls, each costing £3.
Mrs Thomas described the stalls, which have been made from wooden pallets, as “quite unique and rustic”.
The allotment group won the allotment category at the Wales in Bloom competition on Friday, September 13.