The National Botanic Garden in west Wales is close to a deal with a Cardiff development firm, BBC Wales has learnt.
The garden has looked at investment by private-sector firms
One of the options may be to build a retirement village in the grounds of the attraction which last year needed a £1.3m rescue package to stay open.
Another bidder had planned to build an eco village with health spa and lodges but the idea has not been taken up.
The garden, which cost more than £40m to set up, saw visitor numbers slump after it opened in 2000.
A spokesperson for the garden declined to go into details about what the likely land deal might mean but said its selection of development partner at this stage was made for financial reasons rather than on planning proposals.
In 2003, the 500-acre gardens at Llanarthne, Carmarthenshire, were on the brink of closure after the decline in visitor numbers and rising debts put it into crisis. Culture Minister Alun Pugh rejected calls for a £3m assembly bail-out.
A three-party rescue deal was eventually struck between the assembly government, Carmarthenshire County Council and the Millennium Commission.
Visitor numbers have risen since a £1.3m rescue package last year
Bosses at the gardens have been keen to stress how they are on track to achieve their aim of increasing visitor numbers by about 5-7% a year.
BBC Wales has learnt they have also been looking at a number of options for developing the site with private-sector investors.
One of the terms of the bidding process was for competing firms to promise an upfront payment of £1.4m.
The garden is currently at the early stages of an agreement with a firm called Mansford Holdings plc.
According to the firm's website, it is looking to invest in building retirement villages in the UK.
One of the bidders which missed out was a consortium called KTP. Its plan was to build an eco village in the grounds, with tree lodges and a health spa.
The idea was to take elements from the successful Eden project in Cornwall and create somewhere where people could stay.
No-one was available for comment from Mansford Holdings plc.