In the agriculturally important southern lake-shore region of Uganda the topography is typically highly dissected with small flat-topped hills often separated by swamps. Although relief is moderate, and its maximum amplitude is commonly of the order of 300-400 ft only, local climate can vary considerably from place to place. At Makerere University College Farm, Kabanyolo, where the range of altitude is just over 200 ft, the diurnal ranges of temperature on the hill top and lower slopes can be 17? C and 270 C respectively, and both the amount and duration of dewfall are greater in the lower than in the higher areas (Huxley & Beadle 1964). Such differences in local climate may well be of agricultural importance. In the preliminary study reported in this paper, an attempt was made to measure their effects on the growth of seedlings of four common crop species: tomato, maize, cotton and field beans (Phaseolus vulgaris). Standard sand culture was used in order to eliminate from the comparisons the effects of the catenary variation in soil which is characteristic of this area.