Alma contrasts the nourished seed with one that is not tended. Such a seedling does not gain root and is shriveled by the same sun that nourishes the tended seed. We all live in the same world, and many of the same cultural influences impinge upon us. If we do not actively nourish our gospel understanding, the world has many scorching suns. For many, science can become an excuse to abandon God’s word because it is seen as something with more substance.
A strong, even scorching, sun will actually make the plant thrive when it is stronger. Alma stresses that such a failure is not a failure of the seed but rather of the farmer.
Reference: Joseph underwent a period of time where he might not have nourished his tree as well he might. He did not deny his original knowledge and testimony but neither did he progress:
During the space of time which intervened between the time I had the vision and the year eighteen hundred and twenty-three—having been forbidden to join any of the religious sects of the day, and being of very tender years, and persecuted by those who ought to have been my friends and to have treated me kindly, and if they supposed me to be deluded to have endeavored in a proper and affectionate manner to have reclaimed me—I was left to all kinds of temptations; and, mingling with all kinds of society, I frequently fell into many foolish errors, and displayed the weakness of youth, and the foibles of human nature; which, I am sorry to say, led me into divers temptations, offensive in the sight of God. In making this confession, no one need suppose me guilty of any great or malignant sins. A disposition to commit such was never in my nature. But I was guilty of levity, and sometimes associated with jovial company, etc., not consistent with that character which ought to be maintained by one who was called of God as I had been. But this will not seem very strange to any one who recollects my youth, and is acquainted with my native cheery temperament. (JS—H 1:28)
Joseph confesses this period as one of little progress. It was not until he took positive action to nourish his young faith that he made significant progress.