After any nursery has been inspected, the nurseryman may demand of the department a certificate stating the condition of the stock on the inspected premises, and the department shall issue a certificate in accordance with the facts found.

If the inspection shows freedom from dangerously injurious insects, or from such as are liable to become so, the department shall issue a certificate to that effect, specifying in such certificate the date up to which it shall remain valid; but the department may impose as a condition that the nurseryman comply with the requirements of section 4:7-28 of this title, and this condition must be accepted in writing by the nurseryman.