Source: Tafsir al-Ahlam al-Kabir (Ibn Sirin)
Barley in a dream is lawful money with health of the body. It is better than wheat in some aspects. Barley flour indicates religion and guidance.
Source: Ta'tir al-Anam fi Ta'bir al-Manam (Al-Nabulsi)
Barley indicates a short-lived son or little, blessed sustenance. Whoever sees himself plant it has done a righteous deed.
Source: Al-Isharat fi Ilm al-Ibarat (Ibn Shahin)
Barley is interpreted as wealth. Whoever sees himself eat it will gain lawful money.