Marlow Soil Series

The Marlow soil series is New Hampshire's official state soil. It sits on the hillsides, ridges, and upland benches that cover most of the state — the rocky, glaciated terrain that gives New Hampshire the name Granite State.

Marlow is a spodosol, the soil order that forms under conifer and mixed forests in cool, humid climates. Acidic rainfall moves iron, aluminum, and organic matter out of the surface layers and deposits them deeper in the profile, creating two of the most distinctive features in American soils: a bleached pale gray zone just below the surface, and a vivid reddish-brown zone beneath it.

The soil sits on dense, compact glacial till that acts as a hard floor at roughly two feet depth. This dense till restricts roots and slows drainage, often causing a thin layer of water to perch above it in wet seasons.

New Hampshire's soil scientists and the USDA Natural Resources Conservation Service identified the Marlow series as the soil that best represents the state's landscape: thin, rocky, acidic, forest-covered uplands formed in glacial till across the hills and valleys of the Granite State.

The series is named for Marlow, New Hampshire, a small town in Cheshire County in the southwestern part of the state. Naming soil series after nearby towns, ridges, or streams is standard USDA practice.

Marlow soil was chosen because it reflects what most New Hampshire land actually is: not farmland or river bottomland, but forested hillside — rocky, well-drained to moderately well-drained, acidic, and shaped entirely by glacial ice and forest chemistry over 14,000 years.

The Marlow profile is one of the most visually dramatic in the United States. A student digging into a forested hillside in New Hampshire would pass through dark forest litter, a thin black mineral layer, a pale gray bleached zone, and then a sudden shift to vivid reddish-brown before hitting hard, compact glacial till at the bottom.

Marlow soil covers the upland hillsides and ridges that make up most of New Hampshire's interior. It sits at moderate to steep slopes, typically 8 to 35 percent, on the glaciated terrain that stretches from the Lakes Region north through the White Mountains foothills.

The soil is found in every county in the state but is most extensive in Cheshire, Sullivan, Merrimack, Grafton, and Carroll counties — the central and western hill country where the rocky, glacially scoured landscape is most continuous. It also appears in Belknap and Hillsborough counties on upland slopes away from river valleys.

Timber is the primary land use on Marlow soil. The forested hills of New Hampshire support northern hardwoods — sugar maple, yellow birch, and American beech — along with conifers including eastern white pine, red spruce, and balsam fir. These forests have supported logging, maple syrup production, and firewood harvesting for generations.

Sugar maple is the most economically significant tree on Marlow soil. New Hampshire ranks among the top maple syrup-producing states in the country, and the sugar maple stands on rocky upland soils like the Marlow series supply the majority of that production.

Where hillsides have been cleared, Marlow soil can support hay fields and pasture, though the short growing season, rocky surface, and thin soil profile limit crop options. Blueberries grow naturally in the acidic Marlow landscape, and Christmas tree farms operate on some cleared slopes.