Decomposed Granite, Rock and Gravel Delivery in Glendale, AZ

Flat Gilman Loam on Young Desert Deposits

At the center point of ZIP 85301, the USDA soil survey maps Gilman loam, 0 to 1 percent slopes. Gilman covers 100 percent of that map unit, and its top mineral layer is loam, a balanced mix of sand, silt and clay.^[1]

This is friendly soil to build on. The survey rates it well drained and places it in hydrologic group B, which means moderate infiltration. Its shrink-swell rating is low, at 1.5 percent, so it barely moves as it wets and dries.^[1]

Under the soil, the state geologic map shows Holocene surficial deposits of silt, clay, gravel and sand, laid down in the most recent stretch of geologic time. The USGS reads the ground at the center point as 1,150 feet above sea level.^[2],[3]

The flatness is worth noting on its own. Land with almost no slope gives water no natural push in any direction, so even a well-drained loam can hold a puddle after a hard storm if the surface has been packed by traffic or construction.^[1]

Weather at the Youngtown Station

The NOAA normals station at Youngtown, AZ, about 8 miles from the center point, averages 8.3 inches of precipitation and 0.0 inches of snow a year.^[4]

Frost barely shows up. Youngtown counts just 4 days a year with a low of 32 F or colder. The median last freeze in spring is January 20, and the median first freeze of the cold months is December 15.^[4]

Heat and sun are the real design forces here. Stone surfaces store warmth and release it at night, plastic edging can warp in direct sun, and bare soil bakes hard. Choosing light-colored stone near the house and shading beds with a cover of rock or mulch makes a yard more comfortable and easier to water.^[4]

A few dry months in a row can make any stone yard dusty. A light hosing settles Decomposed Granite back into a firm crust, and rinsing River Rock now and then keeps its color bright. Neither material needs much else, which is a large part of why rock yards suit a place with only 8.3 inches of yearly rain.^[4]

Decomposed Granite or River Rock for the Front Yard

These two materials cover most desert yards, and each suits a different job. Decomposed Granite is granite weathered into small, sandy grains. Spread it a couple of inches deep, dampen it and roll it, and it packs into a firm, walkable surface. It works well for paths, open areas and seating spots, and it lets water soak through to the loam below.^[1]

River Rock is smooth, rounded stone in mixed sizes. It does not pack, so it stays loose and decorative. It shines in planting beds, around boulders and in dry creek features that handle storm water. River Rock stays in place better than Decomposed Granite where runoff is fast.^[4]

Many front yards combine the two: a field of Decomposed Granite for the open space and bands of River Rock along beds and drainage lines. Lay a woven fabric under either one to keep weeds down.^[1]

Edges hold a stone yard together. Steel edging or a poured concrete mow strip keeps Decomposed Granite from creeping into River Rock beds and keeps both out of the lawn or the street. Set edging slightly above the stone so a broom or blower can clean it without scattering the surface.^[1]

Parking Pads and RV Spots on Level Loam

Gilman loam with low shrink-swell is about as easy a subgrade as you will find. Clear the area, grade a slight fall away from the house and compact the loam. Because the ground is nearly flat, that small slope you add is the only thing moving water off the pad.^[1]

Build the base with Road Base or Crushed Concrete, wetted and rolled in thin lifts. For a heavy trailer or RV pad, go thicker. Asphalt Millings make a dark, durable surface that firms up in summer heat. For a lighter look, finish with 3/4" Crushed Stone or Driveway Gravel over the base.^[1]

Edge the pad with steel or concrete curbing so the stone stays put when tires turn. Plastic edging tends to warp under long hours of hot sun.^[4]

Loam with low shrink-swell is also kind to slabs and walls. Footings for a garden wall or a pergola rest on firm, stable ground once the loose top layer is cleared away, and a few inches of compacted Road Base under a shed or a hot tub pad give a level, lasting seat.^[1]

Irrigated Beds and Shade Trees

Loam holds water and nutrients well, so beds here grow more with less effort than in pure sand. Mix Compost into the top layer of a new bed to improve its structure, or fill a raised box with Garden Soil.^[1]

Shade trees and fruit trees do best in a wide watering basin. Ring the basin with a low berm of Topsoil and fill it with Wood Chips, which keep roots cool and slow evaporation between waterings. With only 4 freezing days a year at Youngtown, planting can happen in most months, though the mild season is the kindest time for new roots.^[1],[4]

For narrow side yards and utility areas, #89 Crushed Stone or 3/8" Crushed Stone gives a neat, even surface that is easy to walk on and keeps dust down.^[4]

Sand and Screenings for Patios and Pavers

Paver patios are popular in the desert because they stay cooler than poured concrete and are easy to repair. On Gilman loam, dig out the turf or loose soil, compact the subgrade, add a firm layer of Road Base and screed a thin, level bed of Concrete Sand on top. Lay the pavers, then sweep Mason Sand into the joints and mist it to settle.^[1]

Stone Dust Screenings give another route to a patio. Packed and rolled, they form a smooth, firm floor for flagstone or for a simple seating area. They drain better than concrete and look natural next to Decomposed Granite.^[1]

Playground Sand belongs in sandboxes and under play sets, where its washed, soft grains cushion falls. A frame and a layer of fabric beneath it keep the sand from mixing into the loam.^[1]

Homes in ZIP 85301

The Census Bureau's American Community Survey counts 24,447 housing units in ZIP 85301. Detached single-family houses make up 32 percent of them. The median home dates to 1977. Owners occupy 40 percent of the lived-in homes.^[5]

Glendale as a whole has 93,736 housing units, 59 percent of them detached houses, with a citywide median build year of 1986.^[5]

Gravel Valet delivers landscape rock, base and soil to apartment communities, older houses and new builds throughout the city.^[5]