4 expts. were carried out to measure the influence of environmental conditions on the ascorbic-acid content of an inbred strain of Bonny Best tomatoes. Two of them were designed to test the influence of macronutrient supply and the others measured the influence of climatic environmental factors. In sand cultures, growth and fruitfulness could be correlated with minor variations in nutrient composition. A population of 1044 plants were grown to maturity in sand culture and supplied with eighty-seven different nutrient solutions, varying from one another in their relative proportions of the macronutrient elements. Gross appearances of the plants are discussed. Quantitative data are presented for growth and fruitfulness and these data are reduced and analyzed by statistical methods. In general, variations in Ca and nitrate produced greater differences in growth and fruitfulness of plants over wider variations of concs. than were obvious with the other elements. Interactions of the effects of various elements were noted. Ascorbic acid content of the fruit was slightly higher in some sulfate-deficient treatments and slightly lower in K and phosphate deficiencies than average values. With these exceptions, no demonstrable effect of mineral nutrient supply on ascorbic acid was observed. Plants grown during the fall and winter produced fruit with approx. 1/2 as much ascorbic acid as was produced by comparable plants during the summer. The location where the plants were grown had an effect upon the ascorbic acid content of the fruit. These effects could not be correlated with differences between soils at the several locations and were apparently associated with differences in the environment of the top of the plant. Significant positional effects on ascorbic-acid content, even in a relatively small trial plot, were observed. A discussion of the possible practical significance of the results obtained is included.