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Forages are important throughout the south-east USA for livestock production and wildlife habitat. However, little is known about how forage species commonly grown in this region influence soil-quality indicators. The objectives of this research were to determine short-term response of soil water-stable aggregates (WSA) and density of fungal hyphae (DFH) to: (i) forage species or mixtures grown at identical soil pH levels and (ii) forage species or mixtures grown at field-state versus adjusted soil pH levels. Nine warm-season species (sole crop) and eleven cool-season sole crop or legume “grass mixtures were grown under protected culture in southern coastal plain soil microcosms. Levels of WSA and DFH, and plant shoot and root biomass were evaluated after two 12-week experimental growth periods in both field-state and adjusted-pH soil. Both warm- and cool-season forage species significantly altered short-term responses of WSA and DFH levels; these responses differed when the soil pH was adjusted from the field state with lime addition. The short-term responses of both WSA and DFH to lime addition in coastal plain soil were negative only when certain forage species were grown, and no response was detected for the control. It appeared that differences in plant shoot and root developmental characteristics played a key role in soil WSA and DFH responses to the species studied. Further long-term studies are needed to understand how these relationships are expressed in more variable environments over expanded time frames.