Continued addition of sphagnum peat to a clay soil in greenhouse benches over a number of years has resulted in a decrease in wettability, according to observations recently confirmed by laboratory evaluation. Water did not penetrate easily, and many of the soil particles remained dry following irrigation. There is no practical method known at this time for preventing the development of non-wettability in these soils, but certain management practices reported here may be helpful in coping with this problem.