Cal. Bus. & Prof. Code § 12930
As used in this article "cotton" includes raw cotton, cotton linters, and cotton batting. Notwithstanding any other provision of this code or any other law, cotton may be sold by gross weight so that the purchaser pays a like price for the cotton and the burlap, paper, or other material with which it is wrapped and the string, wire, or other material with which the wrapping is secured. When sold by gross weight cotton shall be wrapped and the wrapping secured in accordance with the usual customs of the trade or in accordance with the agreement of purchaser and seller.
A weighmaster may use a tare weight for baled cotton specified by regulations of the United States Department of Agriculture for determining the net weight of cotton.
The tare shall not exceed five percent (5%) of such gross weight.
The provisions of this section shall not be construed to apply to the sale of cotton or cotton goods in any form packaged for distribution or sale at retail to the general public.
Ca. Bus. and Prof'l. Code § 12930