A method is provided for inhibiting plant growth by inducing hypothermia by applying a treating substance to summer annual weeds and grasses. Susceptible undesirable plants will be killed by this treatment, while non-susceptible desirable plants will not be adversely affected by this treatment. Compressed carbon dioxide may be applied to other summer grasses to cause the grasses to become dormant. An apparatus is provided for inducing hypothermia in undesirable plants by applying a treating substance. A canister capable of housing gas may be provided. A valve may be provided to control the amount and pressure of gas dispensed from the canister.