GRAINCORP will close its 2012-13 Harvest10 pool next Wednesday.

Grain delivered into the Harvest10 pool is marketed from time of receival until the following October.

GrainCorp pools manager Stuart Clarke said the October finalisation of sales gave enough time to market the pool effectively while making the final payment just prior to the coming harvest.

The pool offered various payment options to growers.

Currently, the estimated pool return for the Harvest10 pools for Australian Premium White 1 grade wheat is $348 a tonne, delivered Geelong.

Mr Clarke said the global grain market had weakened over the past two weeks.

"The market may take some direction as the US, European Union and Black Sea winter crops emerge from dormancy," he said.

"Meanwhile Australian values have been somewhat protected from the weakness as exporter and trade buying provide support."