In order to study the effect of biofertilizers including mycorrhiza, Azotobacter and Azospirillum, and foliar spray of citric acid on vegetative traits of basil (Ocimum basilicum L.) a factorial experiment was conducted in the form of a randomized complete block design with four replications. Before planting, seeds were inoculated with mycorrhiza, Azotobacter and Azospirillum. Citric acid was applied as a foliar spray at a rate of 5 mM at 5-6 leaf stage. Results showed that foliar spray of citric acid significantly increased shoot fresh weight, shoot dry weight, root fresh weight and root dry weight. Mycorrhiza, Azotobacter and Azospirillum had no significant effect on these traits. Three-fold interaction of citric acid × Azotobacter × mycorrhiza had significant effect on the studied traits. Citric acid × Azotobacter × mycorrhiza produced the highest amount of shoot fresh weight, while the highest shoot dry weight was produced by citric acid × azospirillum. Citric acid × mycorrhiza produced the highest root fresh weight, whereas the highest root dry weight was produced by Azotobacter × mycorrhiza.
