Samples of irrigated ryegrass pasture and natural veld from various parts of Natal were found, with one exception, to lack the amount of Se normally considered sufficient (0.1 mg kg−1) for grazing animals. No soil properties could be identified by multiple regression as causing such a deficiency. Ryegrass was grown in pots filled with a Kranskop topsoil collected from a selenium-deficient pasture. Sodium selenate, selenite (mixed evenly with the soil or placed in a localized application), Selcote (selenate-based, slow-release granules) and fly ash (containing about 10 mg kg−1Se) were factorially compared at Se rates of 0.5, 1 and 2 mg kg−1in the presence of gypsum and lime. Sodium selenate and Selcote (to a lesser degree) increased foliar Se in ryegrass over a 15-week period to levels normally considered toxic to livestock (>4.0mg kg−1). Gypsum and lime decreased Se uptake by one and a half to three times. Selenite boosted foliar Se to adequate (>0.1 mg kg−1) but not toxic concentrations. Fly ash produced adequate foliar Se only at toxic and economically prohibitive concentrations of ash (20% of the soil). Selenite would be safer than selenate-based fertilizers for rectifying Se deficiency in pastures, but would be needed in larger amounts and would therefore be more costly.