The study investigated the fertility of soils under Caladium, Costus, Setaria and Imperata in 10 locations of southeastern Nigeria. Soil samples were collected at random on soils formed over coastal plain sands of southeastern Nigeria. Soil samples were bulked, quartered and air-dried before laboratory analysis. Soil samples were sieved using a 2-mm sieve and analyzed for some soil fertility indices. Variation in soil fertility indices were computed using analysis of variance (ANOVA) while means were separated with least significant difference (LSD) at 5% level of probability. Calcium- magnesium ratios varied significantly (p=0.05) among plant species, and values ranged from 3.6 (Caladium). Setaria (1.9), Costus (1.7) and Imperata (0.8). Nitrate-nitrogen differed significantly (p=0.05) among plant species and distributed as follows: 0.13 g/kg (Caladium), 0.12g/kg (Setaria), 0.11g/kg (Costus) and 0.08 g/kg (Imperata). Base saturation values decreased in the order of Caladium (56%), Setaria(49%), Costus (41%) and Imperata (21%). These soil parameters had significant (P< 0.05) positive relationships with total carbon. It can be concluded that soils under Caladium can be used to infer greater soil fertility in farmland.