What is the test for a warrantless search of a constitutionally protected area?

The recent case of People v. Bradley, 1 Cal.3d 80, 81 Cal.Rptr. 457, 460 P.2d 129, is of interest on the question of a warrantless search of 'constitutionally protected areas,' more particularly, the legality of a search of grounds adjoining a house occupied by a defendant. In that case, on facts remarkably similar but not as strong as the facts of this case on the [3 Cal.App.3d 786] validity of the search, the court held lawful a seizure of marijuana plants growing in a yard 20 feet from defendant's door where 'presumably delivery men and others came.' Noting that the evidence of defendant's possession was not overwhelming, the court, nevertheless, held that, under the facts and circumstances, an expectation of privacy on the part of defendant with respect to the area where the marijuana plants were growing would have been unreasonable, and, therefore, the area was not constitutionally protected. Accordingly, admission of the plants in evidence was held not to be error. The case was reversed, however, because the contraband seized inside defendant's home was admitted in evidence despite a clear violation of his Fourth Amendment rights proscribing unreasonable searches and seizures.