The Philistine city of Ashkelon, situated on Israel's southern shoreline, was destroyed by the troops of the Babylonian king Nebuchadnezzar in 604 BCE. The plant remains collected systematically during the current excavations provide for the first time insights into the economic activities of this port town. Staple food, cereals, pulses, and fruits were found in large quantities. We employed the weed species not natural to the Ashkelon area as markers for locating wheat fields farmed in the city's hinterland. We found that a portion of the wheat came from the east, as far away as the Judean Hills and the northern Negev; while another portion was shipped from the northern part of the country. In addition, we demonstrate that the appearance of large quantities of uncharred nutlets of blue bushy bugloss (Echiochilon fruticosum var. sieberi) on the site's floors is a marker for the use of sand as a construction material. The identified plant remains agree well with our knowledge of 7th century BCE Ashkelon as a major commercial center. It also indicates the sweep of activities related to the storing of food before the city came under Babylonian siege.