A field study was conducted on rosemary plants (Rosmarinus officinalis) in newly reclaimed sandy soil at Siwa Oasis in Egypt's Sahara. The goal was to find the best dry yeast extract concentration for spray, cultivation distance, and interaction to maximize yield. These issues have yet to be researched in the context of this region. The investigation was carried out using a split-plot design. The main plots were sprayed with four doses of dry yeast extract: 0, 8, 12, and 16 g/liter. The subplots involved cultivation at three different plant-to-plant spacings: 30, 50, and 70 cm. Growth, yield, and essential oil characteristics were recorded as data points. Our findings showed that raising yeast extract concentrations increased development and production. Growing at a close distance of 30 cm yielded the most herb and essential oil production per hectare, although planting at a greater distance boosted fresh and dry weights per plant. The essential oil had high concentrations of α-pinene, 1,8-cineole, camphor, and borneol. To increase the producers' income under these environmental conditions, we recommend growing rosemary at a distance of 30 cm and spraying it with yeast extract at a dosage of 16 g per liter.