Methods for delaying the maturity, coloration and/or senescence of fruits, vegetables, ornamentals, or non-food crops by applying phosphorous acid and/or its salts to the plants； or by applying mixtures of gibberellic acid and/or its salts and phosphorous acid and/or its salts to the plants. Applications may be made pre- or post-harvest at various temperatures and pH ranges. The unique combinations of phosphorous acid/salts with gibberellic acid/salts in embodiments of the present invention have been found to increase the effect of the gibberellic acid/salts on delaying maturation, coloration and senescence of plant tissues, thereby prolonging the shelf life of fruit, vegetables and/or non food crops in ways not previously realized.
