Upon receiving the petition and determining its adequacy, the board of directors shall set it for hearing and give notice of the time and place of the hearing by causing notices to be posted in 3 public places in the special improvement district at least 10 days before the date of hearing. The board shall also cause a copy of the notice to be published in a newspaper of general circulation printed and published in the county in which the greater portion of the district is situated, and circulated in the special improvement district, once a week for at least 2 weeks prior to the date set for hearing, with the first publication at least 10 days prior to such date.