Florida citrus production is strongly affected by soil properties which are not always delineated by soil series. Soil heterogeneity was studied in a greenhouse experiment using two sandy soils from productive and unproductive areas of a citrus grove. The study consisted of seven treatments viz; Control, Organic matter removed, Sand particle coatings removed, Sterilized soil, Zeolite, Mycorrhizal inoculation, and N-fixing bacterial inoculation. Forage sorghum was used as an indicator crop. Neither soil was found to be water-repellent. Organic matter and Mehlich I extractable nutrient concentrations were significantly higher in the productive soil than the unproductive soil. When organic matter and coatings were removed, sorghum shoot mass grown on unproductive soil was significantly greater than on the productive soil. None of the amendments proved to be effective in the unproductive soil, but non-significant growth effects with zeolite and N-fixing products were noted in the productive soil. Root dry matter, N concentration and N uptake did not differ significantly for any of the treatments, but the productive soil had higher sorghum dry matter and N uptake than the unproductive soil. Results indicated that the soil organic matter is the main factor limiting productivity on these soils and organic amendments may improve growth of citrus in the unproductive areas of groves. More extensive research is necessary to understand the complex interactions of soil physical properties, coatings on sand particles, soil mineralogy, chemistry and water characteristics in order to identify practical ameliorants for soil improvement.