The Prince George’s County Planning Board has postponed until next week a key vote on the approval process of the development that would include the county’s first Whole Foods Market.

After eight hours reviewing the case, the five-member panel adjourned at 8 p.m. Thursday and will reconvene next Thursday. A planning board vote is one of the final steps before the developer of the 37-acre site in Riverdale Park can pursue permitting and start construction.

The $250 million project will include the grocery store, multifamily housing, a hotel, and office and commercial space at wooded land on Route 1, north of East-West Highway.

The Planning Board last week approved a preliminary site plan for the project and yesterday started to review a more detailed plan among other requirements in the approval process.

County Executive Rushern L. Baker III supports the plan, but it has faced resistance from some area residents who oppose the density of the project and worry about the additional traffic it will bring to the already congested Route 1 corridor.