Wood panels are in the greatest danger of bowing when in high humidity and moisture-rich environments. In fact, many wood panels bow in storage because of such conditions. While it is conventional thinking that once a wood panel is bowed it is no longer of use, that is far from the case. It is possible to remove the bow from a panel, but the process takes time, patience and the right conditions.
Lay the panel flat in a room with little or no humidity so that the bowed ends face downward. The drop in humidity and effects of gravity will flatten the panel slightly while it dries out.
Move the panel outside on a warm morning. This is usually best if the temperature is expected in the 80- to 90-degree range.
Spray a section of a grass lawn with a garden hose. You don't want standing water, but for the ground and grass to be thoroughly damp. Spray a section of the yard large enough to fit the panel plus an additional foot around each side.
Place the wood onto the wet section of grass with the ends down, and the raised hump section lifted into the air.
Examine the board occasionally throughout the day to check its progress. By the end of the day, the board should show signs of improvement. For severely warped boards, it may take a few days of this treatment to level it out.
Dry any condensation that remains on the wood from the day in the sun and wet grass with a towel. Return the panel to the low humidity location overnight and check it again in the morning to see if you need to repeat the process.
Choose a section of yard that receives little or no shade during the day.
Never walk on or set something heavy on the panel to correct the warp. Forcing the wood into another shape weakens the wood.