German potash miner K+S  is making progress in the planned sale of its garden fertilizer unit Compo and is aiming to strike a deal at the end of next month as it focuses on its main salt and potash units.

The sales process would move from the second phase to the final stage this month, and an agreement could be struck as early as end-June, the head of K+S's fertilizer unit Joachim Felker said at the group's annual shareholder meeting on Wednesday.

"There are several (potential) buyers. We want to conclude this process as soon as possible," Felker said.

The world's fourth-largest potash miner hired Goldman Sachs for a strategic review of the unit in June of last year. Compo makes about €400 million ($576 million) in annual sales from specialty fertilizers and potting soil for garden plants.