"Its nearly there", Marshall told Horticulture Week on 29 January.
The refinancing is required to keep the 122-centre chain afloat.
Marshall said four firms of lawyers, three firms of accountants, one bank, shareholders and a "deluge of documents" had made the refinancing "complex and long drawn out".
The agreement will see debt in the company swapped for equity with bank HBOS.
In July 2008 HBOS rolled over a £359 million bridging loan made to Wyevale Garden Centres parent company, Sir Tom Hunter's West Coast Capital (Hortis).
Marshall added: "Documentation is agreed. This is the final going backwards and forwards. It will be done by Monday."
Meanwhile environmental consultant Alan Knight and plant buyer Neil Fishlock have left the company. Fishlock has moved to a similar role at Dobbies Garden Centres.
A Wyevale representative said of Knight: "He was a consultant to the business, not an employee, and he left several months ago on positive terms having helped map out Wyevale's environmental policies."