Gravel, Stone and Soil Delivery in Nampa, ID

Loam at the survey point

The USDA soil survey maps Draper loam, 0 to 1 percent slopes, at the ZIP's center point. The Draper series fills 90 percent of that map unit. Its top mineral layer is loam, the balanced mix of sand, silt and clay that gardeners tend to hope for, crumbly when moist and neither sticky nor loose.^[1]

The survey rates the Draper soil moderately well drained and places it in hydrologic group B, moderate infiltration. Water soaks in at a steady rate and does not linger long, although the soil can stay damp a little longer than a sandy one after heavy irrigation or melt.^[1]

Shrink-swell is low, at 1.5 percent, so the loam barely moves with wetting and drying. On a 0 to 1 percent slope, the bigger issue is flatness. Water has little natural fall, and a drive or a patio has to be built with its own slope to keep it from standing in puddles.^[1]

Loam also compacts easily under heavy equipment, especially when damp. Keep trucks and skid steers to one path during a project, and loosen any packed soil in future planting areas with a fork before adding Compost or Topsoil. Ground that has been driven on stays hard and sheds water, while loosened loam takes in irrigation evenly and lets roots spread.^[1]

Basalt beneath the loam

The geologic map places a basalt unit at the ZIP's center point, labeled Basalt (Pleistocene and Pliocene). Basalt is a dark, dense volcanic rock that formed from cooled lava flows. It is hard and heavy, and where it sits close to the surface it can stop a post-hole digger or a trencher.^[2]

Most home projects never reach the rock, since loam and other loose deposits cover it. When a deep dig does hit basalt, building up with compacted Road Base or Fill Dirt is easier than breaking through. The rock's presence is a good reason to test-dig a few spots before planning a long fence line or a deep drain.^[1],[2]

Basalt also comes into play for drainage. Where the rock lies close, water that soaks through the loam may meet it and spread sideways. A French drain filled with Drain Rock, set above the rock and leading to a ditch or a lower part of the lot, clears a wet patch better than a deep pit that has nowhere to empty.^[1],[2]

Dry air, light snow and cold nights

Weather averages come from the NOAA normals station at Nampa Sugar Factory, ID, about 2 miles from the ZIP. It averages 11.0 inches of precipitation a year, a dry total that makes irrigation part of almost every lawn and garden plan.^[3]

The station averages 9.7 inches of snow a year and counts 132 days a year when the low reaches 32 F or colder. Snow rarely piles deep, but cold nights are frequent. Water from irrigation or melt that collects on a drive can freeze overnight and loosen the top stone, so drainage and a crown still matter even in a dry climate.^[3]

At Nampa Sugar Factory the median last spring freeze is April 29. The median first fall freeze is October 13. Tender plants go in after the April date, and beds should get a fresh layer of mulch before the October date.^[3]

The ground at the center point stands 2,450 feet above sea level.^[4]

Dry, windy weeks also make dust a common complaint on bare ground. A cover of stone or mulch over any soil left bare after a project keeps it in place. #57 Crushed Stone over fabric suits a utility strip beside a garage, and Wood Chips suit the ground under trees, where the light snow cover melts quickly and leaves the soil exposed.^[3]

A driveway on flat loam

Start by stripping sod and dark topsoil, then grade the loam into a gentle crown or a slope to one side. On flat ground, this step creates all the drainage the drive will have. Compact the subgrade with a plate compactor. Loam carries weight well when compacted and dry, so fabric is optional, but it helps keep the base clean on low spots that stay damp.^[1]

Spread Road Base in thin lifts, wetting and compacting each one until it stops moving. Crushed Concrete makes a solid alternative. For a heavy-use pad that holds a trailer or a camper, add a lower course of 1-1/2" Crushed Gravel or #4 Crushed Stone first. Finish with 3/4" Crushed Stone or Driveway Gravel. Along the low edge, a shallow ditch of #57 Crushed Stone lets irrigation runoff and melt soak into the ground instead of freezing on the surface.^[1],[3]

Asphalt Millings give a firmer, darker surface that resists dust in dry weather and holds together under turning wheels. They shed water rather than taking it in, so they need a clear crown and an edge where runoff can drain away.^[1],[3]

Paths and patios on flat loam follow the same rules as the drive. Compact the subgrade, add a layer of Road Base, and finish with 3/8" Crushed Stone, Walkway Gravel or Stone Dust Screenings for a walk, or set pavers on Concrete Sand over the base for a patio. A slight slope away from the house keeps irrigation water off the foundation.^[1]

Compost or Topsoil for a garden

Draper loam is a good starting point for a garden. The real question is what to add. Compost brings organic matter and life to the soil. Worked into the top layer each year, it improves structure, feeds plants slowly and helps the loam hold water in the dry months. It is the right choice for an existing bed with decent soil.^[1]

Topsoil adds volume. It suits a new bed built up above grade, a lawn that needs leveling, or a spot where construction stripped the original soil away. A blend of Topsoil and Compost gives a deep, rich root zone, and Garden Soil comes ready-mixed for raised beds. Cover the surface with Brown Shredded Mulch or Wood Chips to slow evaporation, since the station records only 11.0 inches of precipitation a year. Black Shredded Mulch and Red Mulch work the same way with a different look.^[1],[3]

Homes in ZIP 83651

The Census counts 14,627 housing units in ZIP 83651. Nampa holds 40,529 units in total.^[5]

Detached single-family houses make up 73 percent of homes in ZIP 83651, close to the Nampa share of 75 percent.^[5]

The median home in ZIP 83651 was built in 1991, while the Nampa median is 2000. Owners occupy 73 percent of the occupied homes in the ZIP. ZIP 83651 is in Canyon County, and Gravel Valet also delivers to Meridian and Boise.^[5]