Two field experiments were performed at the Baramoon Experimental Station, Dakahlia Governorate, Egypt, during the two seasons of 2009/2010 and 2010/2011 to study the effect of two sowing dates (15 Oct. and 15 Nov.) and foliar application with lupine seed extract at various concentrations of 0, 5, 10, 15% as well as their interaction on foliage yield, chemical composition, seed yield and seed quality of spinach plants cv. Dokki as well as associated weeds. A split plot design with three replicates was used. The obtained results revealed that sowing spinach on mid-October resulted in marked increases in plant height, number of leaves per plant, foliage fresh weight per plant, total yield per fedden, dry matter percentage of leaves, nitrate content of leaves, seed production and its quality as well as associated weeds fresh weight, compared with that sown on mid-November in both seasons. Results also cleared that foliar application with the relatively high used concentration of 15 % lupine seed extract had significant promotion for most of the studied characters except associated weeds fresh weight, dry matter percentage of leaves and nitrate content of leaves which were significantly decreased as compared with the control treatment in both seasons. The interaction effect of sowing date and foliar lupine seed extract exhibited significant effect on all studied traits in both seasons. Generally, it could be concluded that sowing spinach cv. Dokki in mid October interacting with application of lupine seed extract at 15% concentration was found to be the best management system for increasing foliage yield, its quality, seed yield and seed quality under the environmental conditions of Dakhlia district. Moreover, applying lupine seed extract could be considered a powerful and environmental friendly approach to improve plant growth, quality and production, and it might open the door for new strategy for controlling the weeds in spinach fields.