The experiment was carried out in the area of Chiman, which is about 15 km from the center of the city of Kirkuk during the Agricultural season (2018_ 2019) to study the response of two varietiesof broccoli Brassica oleracia var.italica to the spraying levels of seaweed extract and different planting dates according to the split-split-plot Experiment in Randomized Complete Block Design(RCBD) with three replicates. The experiment included 36 experimental units which is a consensus between three factors, including the experiment (2 * 2 * 3) where the varietiesput in the main plots. The first variety (Polo F1) and the second variety (Paraiso), and the dates of planting is 10/10/2018 and 25/10/2018, and spraying with Acadian sea weed extract in three concentrations (0,
1.5, 3) g/l. The treatment was repeated three times. The differences between the averages were tested according to the Duncan Multiple Range Method, the results showed that the effect of the varieties showed significant effect in the stem diameter, leaf dry weight, head dry weight, chlorophyll content and the number of secondary heads but did not significantly affect the head diameter and head branch number and the leaf area, and for planting dates were insignificant at the probability level and for all vegetative characteristics. The effect of spraying sea weed extract was significant in head diameter, number of head branches and leaf area, and did not significantly affect stem diameter, number of leaves and leaves, head dry weight, chlorophyll content and secondary heads. Interaction between broccoli Hybrids and planting dates, and between broccoli varieties and levels of spraying significantly affect all vegetative characteristics. The effect of interaction between planting dates and spraying levels of sea weed extract was significant in head diameter, number of head branches, dry leaves weight , chlorophyll content, and leaf area and did not significantly affect stem diameter, head dry weight and number of secondary heads.