The Botanical Gardens are situated in the northwestern corner of Heidelberg within the communal field district called "Neuenheimer Feld" to the west of the quarter Neuenheim on a shallow terrace along the Neckar river. The river curves around to the northwest as it exits the narrow Neckar valley and the elevated slopes of the Odenwald, and meanders slowly into the lowlands of the upper Rhine valley where it eventually leads into the Rhine River at Mannheim some 15 miles from Heidelberg. The area of the Neckar river's "delta" at Heidelberg is characterized by red sandstone sediments deposited mainly during the Pleistocene.
The low terrace on the northern banks of the river, where the Botanical Gardens are located, was formed during the last Glacial period as a 25-m-thick deposit of sand and gravel. At the end of the last Glacial period the river covered this coarse layer with a 1-m-thick sheet of fine alluvial loess and silt. During the Boreal period the water level was gradually lowered by the river carving into these sediments. Starting in the Atlantic period (ca. 7500 years ago) these semiterrestrial floodplain soils were colonized by mixed deciduous forests of oaks, elms, and hornbeams such that the brown to black floodplain soils further developed into terrestrial brown podzols.
The fertile soils within the Neckar delta region attracted people who established first settlements at the end of the Neolithic. As of the beginning of the Bronze Age this led to first deforestations of the higher terraces, which, during Roman time, were permanently converted into farmland.
Prior to construction of the Botanical Gardens in 1915 the fields of the Neuenheimer Feld were mainly strip-farmed with crops, some gardens, and meadow-orchards. Today's soils are fine sand to silty aged podzols characterized by loamy surfaces at pH 6.5–7.4.
