The conditions under which a spectrum of lower hybrid drift waves will decay into low‐frequency drift waves (LFD) are calculated. The purpose is to help understand why lower hybrid drift waves are not seen in all field‐reversed configuration (FRC) experiments in which they are predicted. It is concluded that if there is in the plasma a LFD wave amplitude above a critical level, lower hybrid waves will decay into low‐frequency drift waves. The critical level required to stabilize TRX‐2 [Phys. Fluids30, 1497 (1987)] is calculated and found to be reasonably consistent with theoretical estimates.