The Foundation for Appalachia Ohio provides numerous mini-grants throughout the year

The Captain Planet Foundation has grants for many environmental and STEM projects. Their site also has links for teacher resources.

The Ohio Department of Natural Resources offers a variety of grants. Schools are able to receive up to $10,000 to start their own land labs. 
Other grants encourage outdoor education and conservation efforts. 

The Innovative Education Award targets programs that use E-STEM
  focusing on environmental aspects of science, technology, engineering, and math