Leonardslee Gardens, at Lower Beeding, will re-open to the public on March 1 2018.
A spokesperson for the gardens says that investment will see an upgrade on the listed buildings which will include a restaurant area.
Facilities for families will be installed too.
Andy Streeter, general manager of the gardens, says he is excited to officially open to members of the public.
He said: “It is amazing to learn about how many people love the gardens when they were open before so we are very excited for March.
“Between now and the next four or five years we will be investing in many areas.
“Every month something will be different. Now is a great opportunity to see the progress of the site.”