Soil moisture tension had a greater effect on both soil surface temperatures and growth of young Kentucky 31 tall fescue (Festuca arundinacea) seedlings under solar radiation than either wood-cellulose mulch or slope-facing. More growth and lower temperatures occurred at low than high moisture tensions. Mulch did not consistently benefit growth. Slope effects were evident primarily at high tensions: higher temperatures and less growth occurred on south than north slopes. Temperatures (a) within a millimeter above the soil-air interface and (b) below the surface of, yet within the mulch layer seemed the most critical to seedling growth. Inadequate moisture control, a sparse seeding rate, a high mulching rate, and below optimal weather conditions complicated environmental control and produced some ambiguous results. A characterization of surface temperature injury to perennial ryegrass (Lolium perenne) seedlings grown with wood-cellulose mulch at two moisture tensions showed seedling injury to increase with surface temperature while air and soil temperatures had no significant effect. Low moisture tension produced lower surface temperatures and less injury than high tension. / M.S.