Gravel, Soil and Mulch Delivery in Hillsboro, OR

Woodburn silt loam on the valley floor

The USDA survey maps Woodburn silt loam, 0 to 3 percent slopes, at the ZIP's center point, and the Woodburn series makes up 85 percent of the map unit. Silt loam is smooth and fine. It digs cleanly when moist, sets hard when it dries in summer, and turns slick when it soaks up winter rain.^[1]

The survey rates the soil moderately well drained, in hydrologic group C with slow infiltration. Water does move down through the profile, just slowly, and during a long wet spell the upper layers can stay damp for days. A gravel surface laid directly on that kind of ground can sink and turn muddy by midwinter.^[1]

Shrink-swell in the top 100 cm rates moderate, at 4.5 percent. The silt loam swells somewhat when soaked and shrinks back in the dry months. Long concrete edges and slabs may crack along the way, while compacted stone flexes and resettles.^[1]

The center point's ground elevation is 180 feet, and its slope class runs from flat to 3 percent. On level valley ground, water does not leave a lot unless grading or a trench sends it somewhere.^[1],[2]

A quick squeeze test tells you the soil's mood on a given day. If a handful pressed into a ball smears and leaves a shiny print, it is too wet to compact or till. Wait until it crumbles when pushed with a thumb, then build. Working wet silt loam seals the surface and makes drainage worse. In this valley that often means doing the heavy digging between late spring and early fall, while the ground is firm enough to carry a loaded wheelbarrow or a small loader without sinking.^[1],[3]

Wet winters and a spring that lingers

Weather normals come from the NOAA station Portland-Hillsboro AP, OR, about 7 miles away. It averages 35.9 inches of precipitation a year, most of it in the cool half of the year, with long, gray rainy stretches and a dry, mild summer.^[3]

The station counts 64 days a year with a low of 32 F or colder. Its median last spring freeze is April 16, and its median first fall freeze is October 23. Freezes are usually light, yet a soaked base that freezes at night can lift and soften, so a dry base matters even where frost is shallow.^[3]

Garden timing follows those dates. Set out tomatoes and tender annuals after mid-April, and plan to cover or harvest them by late October. Fall is a fine time to mulch beds and plant shrubs, since the rains do the watering.^[3]

A patio that stays level

On silt loam with moderate swelling, a paver patio is a better fit than a slab. Dig out sod and topsoil, slope the subgrade away from the house, and compact it on a dry day. Lay woven fabric so the silt cannot work up into the base.^[1]

Compact Road Base or Crushed Concrete in thin lifts, wetting each one, until the layer is hard and smooth. Screed a thin layer of Concrete Sand on top and set the pavers. Sweep Mason Sand into the joints and run a plate compactor over the field to lock it.^[1]

Edge drainage keeps the base dry through winter. A shallow trench of Drain Rock along the low side, wrapped in fabric, collects water that runs off the patio before it soaks into the subgrade.^[1],[3]

A gravel drive on valley silt

The same rules apply to a driveway, with more stone. Over fabric and compacted subgrade, place a layer of 1-1/2" Crushed Gravel where the ground stays soft, then compact Road Base on top. Finish with 3/4" Crushed Stone or Driveway Gravel. Crown the surface so winter rain runs off both edges.^[1]

Rake ruts flat in early fall, before the rains return, and top up thin spots with fresh stone. A drive that goes into winter tight and crowned comes out of it in far better shape than one left rutted.^[3]

Where the drive meets the street, a slight hump or a shallow swale stops runoff from the road washing onto the gravel. Line that swale with #57 Crushed Stone so it keeps draining without turning into a muddy ditch. On a lot with slow-draining silt, every bit of water kept off the drive helps the base stay firm.^[1],[3]

Pea Gravel is tempting for its looks, but on a drive it rolls under tires and sinks into soft ground. Keep it for paths and patio borders, set over a compacted base and held in by a solid edge.^[1]

Wood Chips or Brown Shredded Mulch for a damp garden

Mulch choice changes how a bed behaves through a wet winter. Brown Shredded Mulch is fine and fibrous, so it knits into a mat that stays put and protects bare soil from pounding rain. Wood Chips are chunkier and looser, letting air reach the soil and breaking down more slowly.^[3]

Use Brown Shredded Mulch in planted beds where you want a neat finish and weed control. Use Wood Chips on paths between vegetable beds, under play structures and around trees, where they absorb mud and stay springy underfoot. Black Shredded Mulch and Red Mulch offer the same behavior as brown with a different color.^[1],[3]

Under any mulch, work Compost or Garden Soil into the silt loam first. Organic matter opens up the fine soil so water and roots move through it more easily.^[1]

Lawns on silt loam compact under foot traffic, and compacted ground drains even more slowly. Each fall, core aerate the lawn and spread a thin layer of Topsoil mixed with Compost over the surface, raking it into the holes. Over a few seasons the top layer becomes looser and greener.^[1]

Homes in ZIP 97123

The Census counts 18,057 housing units in ZIP 97123. Detached single-family houses make up 65 percent of them, well above the 47 percent share across Hillsboro. Owners live in 70 percent of the ZIP's occupied homes. The median home in the ZIP was built in 1994, and the city median is 1997. Hillsboro as a whole has 43,576 housing units.^[4]

Oregon highway work uses Dense-Graded Base Aggregate, named in Section 00641 of the Oregon Standard Specifications for Construction (2024). A home patio carries far less, but it gains from the same dense, compacted layer under the surface.^[5]

A large share of detached houses means plenty of yard work: Topsoil to level a lawn before reseeding, bark for foundation beds, and a gravel pad beside the garage for a trailer or a second car. Spring and late summer are the busiest times for this kind of work, while the silt loam is firm enough to build on.^[4]