Various field management systems influence the quantity of photosynthetic light and the far-red to red ratio (FR/R) in light reflected to developing cotton bolls. Previous studies have shown that an increased FR/R results in longer stems and longer cells within those longer stems. Since the cotton fiber is a single elongated cell, we hypothesized that the FR/R reaching the developing boll could influence elongation of fibers. Spaced plants were grown in trickle-irrigated field plots covered with different colored plastic sheets, which reflected different quantities of FR/R up to developing bolls. Fiber lengths were evaluated by AFIS procedures. Soil covers that reflected higher FR/R resulted in longer fibers that were also thinner. Evaluation of fiber physical and chemical characteristics relevant to strength and dye holding ability have been initiated. Relevance of these findings to field management of cotton production is that the FR/R reaching developing bolls is influenced by FR reflected from nearby green leaves (population density), dead plant residue (conservation tillage), and even color of the soil surface.