To qualify for H-2A nonimmigrant classification, the petitioner must:

• Offer a job that is of a temporary or seasonal nature
• Demonstrate that there are not sufficient U.S. workers who are able, willing, qualified, and available to do the temporary work.
• Show that the employment of H-2A workers will not adversely affect the wages and working conditions of similarly employed U.S. workers
• Generally, submit with the H-2A petition, a single valid temporary labor certification from the U.S. Department of Labor

H-2A petitions may only be approved for nationals of countries that the Secretary of Homeland Security has designated, with the concurrence of the Secretary of State, as eligible to participate in the H-2A program.  That list of countries can be found here.