Gravel, Stone, Fill and Soil Delivery in Jackson, MS

Silt Loam on a Floodplain

The USDA soil survey maps the center point of ZIP 39201 as Riedtown silt loam, 0 to 2 percent slopes, occasionally flooded. Riedtown is the main series, at 90 percent of the map unit. The name itself carries the key warning: this is low ground near a river, and high water can reach it from time to time.^[1]

The top mineral layer is silt loam, a soft, floury soil that feels smooth when dry and turns slick when wet. The survey rates it moderately well drained. Its hydrologic group is B/D, which means it behaves like group D, with slow infiltration and high runoff, while the water table is high, and like group B, with moderate infiltration, where it has been drained.^[1]

For a builder, that split rating is a practical clue. Where a site has ditches, drains or raised grades that keep the water table down, the soil takes rain in at a fair rate. Where it does not, water stays near the surface after storms, and every base, bed and walk needs a way to shed it.^[1]

Shrink-swell is low, at 1.5 percent linear extensibility in the top 100 cm, so this soil does not heave and crack like heavy clay. Its weak point is strength when wet. Silt loses grip under a load once it is soaked, and fine particles migrate easily into any stone laid directly on top.^[1]

The USGS state geologic map shows an Eocene unit of clay, sand and marl beneath the soil at that point. The USGS elevation service reads the ground at the center point as 270 feet above sea level.^[2],[3]

Floodplain silt often lies in layers left by past high water, with sandier and finer bands stacked on top of one another. A test hole before a large project shows what you are working with. Soft, dark or wet layers near the surface should come out and be replaced with compacted Fill Dirt or Road Base.^[1]

Heavy Rain and Mild Freezes

The closest NOAA normals station is Jackson Hawkins FLD, MS, about 4 miles from the center point. It averages 51.3 inches of precipitation a year, a high total that comes in frequent soaking rains and strong storms. On silty floodplain ground, that much water makes drainage the first question on every project.^[4]

Winters are mild but not frost free. The Hawkins Field station counts 32 days in an average year when the low reaches 32 F or colder. Wet silt that freezes can heave slightly, so a base that drains well also resists the occasional frost.^[4]

For the garden calendar, the station's median last spring freeze is March 6, and its median first fall freeze is November 19. Spring planting and new sod do well after the March date, and fall is a good time to spread Compost and mulch on beds.^[4]

Long wet spells in winter and spring keep silt soft for weeks at a time. Plan heavy work, such as digging and compacting a base, for a dry stretch, and keep delivery trucks and loaded wheelbarrows off soaked ground where they can leave deep ruts. A temporary path of plywood or crushed stone helps on a muddy site.^[1],[4]

Building a Base That Stays Dry on Silt

Fabric is not optional on silt loam. Dig out the topsoil and any soft, wet material, compact the subgrade, and lay a woven fabric across the whole area. Without it, the fine silt pumps up into the stone every time it rains and the surface turns into a rutted mix of mud and gravel.^[1]

Road Base forms the main layer, spread in thin lifts and compacted while damp. Its interlocking stone and fines create a firm platform that spreads loads over the soft soil. For heavy use, such as a lot that takes delivery trucks, 1-1/2" Crushed Gravel or #4 Crushed Stone makes a coarse, strong lower layer under the base.^[1]

Top the base with #57 Crushed Stone or 3/4" Crushed Stone for a surface that drains quickly after each rain. Driveway Gravel packs tighter if you want a smoother finish. Crown the surface, and add a strip of Drain Rock along the low edge so runoff leaves before it soaks the base.^[1],[4]

On ground that floods occasionally, raise the finished grade where you can. A drive or pad built a little above the surrounding yard, with Fill Dirt compacted in layers under the base, drains faster and recovers sooner after high water.^[1]

Downtown Housing and the Wider City

ZIP 39201 is a small, central residential area. The Census Bureau counts 835 housing units there. Detached single-family houses make up 9 percent of them, and owners occupy 1 percent of occupied units. The median home was built in 1967.^[5]

Jackson as a whole looks very different. The city counts 74,871 housing units, and 66 percent of them are detached houses. The citywide median build year is 1969, close to the figure for the ZIP.^[5]

Projects in a central area like this tend to be commercial lots, apartment grounds and small courtyards rather than private yards. Parking areas, walkways and planting strips around buildings all benefit from the same rules: fabric on silt, a strong base and a clear path for water.^[5]

Parking lots and service drives are a common need here. A lot that takes cars all day needs a thicker base than a home drive, and its surface should drain toward a ditch or inlet. Asphalt Millings make a firm, dark surface for a lot, and they bind together as they are rolled and warmed.^[4],[5]

Beds, Lawns and Low Spots

Silt loam holds water and nutrients well, which makes it decent for plants once it is loosened. It packs hard when walked on wet, though, and it can stay soggy after long rains. Raised beds filled with Fill Dirt blended with Compost keep roots above the wettest layer, and more Compost worked into the top of existing beds improves structure.^[1]

Low spots that pond after storms can be raised with Fill Dirt, compacted in layers, and finished with Compost worked into the top few inches for grass. Where water must cross a yard, a shallow swale lined with River Rock carries it without washing away soil.^[1],[4]

Mulch protects silty soil from crusting under heavy rain. Brown Shredded Mulch, Black Shredded Mulch and Red Mulch all knit into a mat that breaks the force of falling water and slows erosion on bare beds. Wood Chips suit paths and tree rings.^[1],[4]

After a flood, check beds and gravel areas for a layer of fresh silt. A thin coat can be raked into beds, but a thick layer smothers plants and clogs the gaps in a stone surface. Rake it off gravel, top up with fresh stone, and add new mulch to beds once the soil dries.^[1]