(a) The provisions of §§ 1502, 1503 and 1504 of this title do not apply:
(1) To seed or grain not intended for sowing purposes;
(2) To seed in storage in, or being transported, or consigned to a cleaning or processing establishment for cleaning or processing; provided, that the invoice or labeling accompanying any shipment of the seed bears the statement “seed for processing,” and provided that any labeling or other representation which may be made with respect to the uncleaned or unprocessed seed shall be subject to this chapter;
(3) To any carrier in respect to any seed transported or delivered for transportation in the ordinary course of its business as a carrier; provided, that the carrier is not engaged in producing, processing or marketing seeds subject to this chapter;
(4) To seed sold by 1 farmer to another if the seed has neither been advertised for sale nor delivered through a carrier;
(5) To grain sold by farmers for cover crop purposes and not delivered through a common carrier.
(b) No person shall be subject to the penalties of this chapter for having sold or offered for sale seeds subject to this chapter which were incorrectly labeled or represented as to kind, species (and subspecies, if appropriate), variety, type or origin, elevation and year of collection (if required) which seeds cannot be identified by examination, unless he has failed to obtain an invoice, genuine grower's or tree seed collector's declaration or other labeling information and to take such other precautions as may be reasonable to insure the identity to be that stated.
(c) The provisions of §§ 1503 and 1505 of this title do not apply to tree seed produced by the consumer.