For two decades scientists have been using plant growth chambers to make significant contributions in agricultural research. Much too often, haphazard and incomplete environmental measurements have made it difficult, if not impossible, to gain the full utility of this research. Guidelines were developed initially by members of the North-Central Region Technical Committee on Growth Chamber Use. These guidelines are included on a table. The adoption of these guidelines by researchers and adherence to these suggestions by review editors will improve the quality of environmental research and aid in making comparisons among studies conducted in different laboratories.