Soil Conditions by Series

How soil temperature and moisture move through the year at Kent. Nine soil series sorted by drainage class so you can see the pattern: well-drained soils warm faster and dry sooner.

6-year average (2020–2025) · 2026 overlay through Apr

Soil temp thresholds: 40° — Root growth stalls 50° — Warm-season planting safe 60° — Heat-loving species OK
2020–2025 range 6-year average 2026

Soil Temperature

Monthly average soil temperature at 6 cm depth, Kent station. All nine soil series currently reference the same station data. Dashed lines mark planting thresholds.

40° 50° 60° JFMAMJJASOND 35°45°55°65°

Soil Moisture

Volumetric water content at Kent. Higher means wetter. The seasonal swing from saturated winter to dry summer defines which plants survive here.

JFMAMJJASOND 20%30%40%

Monthly Precipitation

Average monthly rainfall at Kent. 2026 bars in dark; average in light. The wet season (Oct–Mar) delivers roughly 75% of annual precipitation.

JFMAMJJASOND 0"4"8"12"

Puget Sound Soil Series

Nine mapped soil series sorted by drainage class. Well-drained soils warm faster in spring and dry out sooner in summer. Poorly drained soils stay cold and wet longer. Knowing your series tells you which pattern your garden follows.

Everett

Somewhat excessively drained Very gravelly sandy loam

Summer drought stress is the primary concern. Water drains through the coarse texture so fast that there is very little stored moisture for plants to draw on during the dry season. Without irrigation, most non-native plantings will struggle from July through September.

Puyallup

Well drained Fine sandy loam / loam over gravelly sand

Flood risk is the main concern. These soils formed from river sediment, and the rivers that deposited them still flood periodically. Check whether your property is in an active floodplain before investing in permanent plantings.

Alderwood

Moderately well drained Gravelly sandy loam

Winter waterlogging: rain pools above the dense layer and saturates roots from December through April. Plants that cannot tolerate wet feet rot during this period.

Bellingham

Poorly drained Silty clay loam to silty clay and clay

True heavy clay — extremely difficult to work

Briscot

Poorly drained Silt loam over stratified silt loam, fine sand, fine sandy loam

Poorly drained with a high water table from November through April. The flat floodplain terrain has minimal slope, so water has nowhere to flow and sits in the root zone for months.

Norma

Poorly drained Ashy loam over sandy loam

Poorly drained because it sits where water naturally collects. The surrounding Alderwood slopes shed water off their dense subsoil layer, and it flows downhill into the depressions where Norma formed. You are not just managing the rain that falls on the Norma soil itself, but also the runoff from the slopes above.

Snohomish

Poorly drained Silt loam over buried organic deposits

Poorly drained with a high water table within a foot of the surface from November through May. The flat floodplain terrain and fine-textured surface layer keep water in the root zone for most of the wet season.

Woodinville

Poorly drained Silt loam

Poorly drained with a high water table from November through April. The flat valley floor has nowhere for water to go, so it sits in the root zone for months.

Seattle

Very poorly drained Muck and mucky peat (organic, not mineral soil)

Very poorly drained. Without artificial drainage, water sits at or near the surface year-round. These were bogs and marshes before development, and the soil still behaves like one.

Data: Open-Meteo API · Kent station · Generated 2026-04-04 21:59 · All soil series currently reference the same station. Per-series moisture adjustment is planned.