Historical information: Lehi and his family are here seen doing the most logical thing. They arrive and construct temporary shelters (verse 23), and then plant the seeds of the familiar crops that they brought with them. The association with the sowing of the seeds and the construction of the tents in verse 23 appears to indicate that Nephi is here describing the earliest aspects of their arrival in the New World. Remembering that Nephi is less interested in history than in spirituality, his account is brief and to the point.
Whatever we might or might not know about Book of Mormon geography, we do know New World dietary patterns, and the New World diet is based on foodstuffs that are indigenous to the Americas rather than imported from the Old World. As a new people in the land, however, it is certain that the Lehites did not know the edible plants of the area, nor the extent of the game animals. It is therefore quite logical that they should carefully plant their familiar foods. That those foodstuffs might not have become staples of the diet of the entire hemisphere is not unusual. It is typical for early cultivations to later disappear (Sorenson 1985 p. 184). This would be particularly understandable as the Lehites learned more of the native crops and game of their new home.