Fluidized bed combustion bottom ash (FBCBA) from coal burning power plants often contain substances that detrimentally affect plant growth [(e.g., boron (B)] when applied to soil. Leaf symptoms similar to B toxicity appeared when maize (ZeamaysL.) was grown during Year‐1 of a field experiment where FBCBA was incorporated (6,790 and 13,580 kg ha‐1) in an acidic soil (Aquic Hapludult). Soil extractable B increased with increased levels of FBCBA in Year‐1 and in Year‐2. Although levels in Year‐2 were lower than in Year‐1 they were still sufficiently high to raise concern about B toxicity. Acquisition of B in leaves of maize grown in Year‐1 was relatively high at the 5‐leaf stage of growth, and at a normal level in the ear leaf; ear leaf B in Year‐1 was greater than ear leaf B in Year‐2. Grain and fodder yields of plants grown with added FBCBA were reduced in Year‐1, but not in Year‐2. A greenhouse study was conducted to determine leachability of B through acidic soil (Typic Hapludult) columns whose surface had been treated with FBCBA at 0, 6, and 12 g kg‐1soil and leached with different amounts of water (25, 200, and 800 mm). Maize was also grown on the leached soil columns to determine effects of compounds leached from FBCBA on growth and B acquisition in leaves. The application of 800 mm of water reduced soil levels of B, and increased the amount of B leached from the columns. Maize shoot and root dry matter (DM) were enhanced with FBCBA. Increased DM associated with higher FBCBA levels may reflect increased soil pH in this acidic soil. Shoot B concentrations decreased with greater amounts of water used to leach columns. Shoot B concentrations were closely related to levels of B present in the 0–15 cm layer of soil in the column and field experiments.