Abstract
The study was conducted at the Department of Horticulture and Landscape, College of Agriculture, Tikrit University, from August 2, 2024, to February 20, 2025. Nine treatments were tested: a control group without spraying, and foliar applications of 50 mg L⁻¹ and 100 mg L⁻¹ boron at 45, 60, 75, and 90 days after transplanting (DAT). The experiment used a Randomized Complete Block Design (R.C.B.D.) with three replications. Data were analyzed using the Least Significant Difference (L.S.D.) test at a 5% probability level. This study aimed to determine the best way to apply boron to the leaves of cauliflower, focusing on the best amount and the best time for it to be applied, in order to improve the plant's growth and how much it produces. The most effective treatment, as determined by all measured traits, was the foliar application of 50 mg L⁻¹ at 60 days after treatment (DAT). This treatment showed the best results for plant height, relative chlorophyll content, stem diameter, flower curd height, curd circumference, and curd weight. The recorded values were 58.90 cm, 3.42 mg per 100 g of fresh weight, 36.16 mm, 19.60 cm, 95.93 cm, and 3.10 kg, respectively. It can be concluded that at 60 days after transplanting, applying boron at a concentration of 50 mg L⁻¹ significantly improved the growth and yield of cauliflower. This suggests that this foliar application method is the best way to maximize both the quality and productivity of the crop