A system and method for hypobaric (low pressure or “LP”) storage of plant matter is disclosed. The method is characterized by controlling the correlated conditions of total pressure, oxygen partial pressure, air intake rate, and pumping speed and additionally controlling the pressure with a vacuum regulator operating at a higher temperature than the storage space; storing plant matter in storage boxes which are unable to adsorb water and release the heat of water condensation; shielding the storage boxes from radiation emitted by the storage space's wall; shielding plant matter in the storage boxes from radiation emitted by the box's inner surface; and decreasing the total storage space pressure and steady-state oxygen partial pressure to a minimum value which does not cause low oxygen injury and is optimally effective in extending storage life, reducing metabolic heat and biochemical energy production, and preventing microbial decay in the plant matter.