The present study aimed to evaluate some growth and biochemical indices of fennel (Foeniculum vulgare L.) under the effect of foliar application of humic acid and date kernel biochar in 2014 under greenhouse conditions. The experiment was carried out as a factorial in a completely randomized design with three replications. The first factor included two levels of humic acid (0 and 2 g/L) and the second factor was biochar at two levels (0 and 1 wt%). The growth parameters measured included shoot length, root length, shoot dry weight and biomass. The biochemical parameters included phenol, flavonoid, soluble sugar, proline and ion leakage. The results showed that the main effect of foliar application of humic acid on shoot length, shoot dry weight, phenol, flavonoid, proline and ion leakage was significant at the one percent probability level and total biomass and soluble sugar at the five percent probability level. And it had no significant effect on other traits. The main effect of biochar on shoot length, proline and ion leakage was significant at the one percent probability level and on root length at the five percent probability level and it had no significant effect on other traits. Also, the interaction of humic acid and biochar on leaf ion leakage was significant at the one percent probability level. Foliar application of two grams per liter of humic acid increased shoot length by an average of 15.92 cm, and the use of biochar increased shoot length by an average of 16.95 cm and root length by 21.74 cm compared to no treatment. Humic acid increased shoot dry weight by 48.18%, biomass by 44.56%, phenol content by 51.25%, flavonoid content by 66.11%, soluble sugar by 48%, proline by 26.43%, and leaf ion leakage by 39.6% compared to no use of humic acid. Biochar reduced proline and ion leakage by 50.92% and 19.89%, respectively, compared to no use of biochar. Also, the interaction of humic acid and biochar resulted in a 38.1% reduction in ion leakage. The results of this study showed that the use of foliar spraying of two grams per liter of humic acid and the application of one percent by weight of date kernel biochar alone can increase some growth traits of fennel plant, and also by increasing phenol and flavonoid, they develop the antioxidant defense system and prepare the plant for cellular defense. By increasing proline and reducing ion leakage in adverse environmental conditions, they can prevent cell water loss.