What Type of Soil Is in Seattle, WA (98101)?
Soil Profile
| Soil Type | Silty Loam |
|---|---|
| Soil Series | Alderwood |
| pH Range | 5.2 - 6.0 (Moderately Acidic) |
| Drainage | Moderately Well Drained |
| Organic Matter | 0.0% (Very Low) |
| Water Holding Capacity | 0.18 in/in (High) |
| USDA Zone | Zone 8b (min 15°F) |
| Hydrologic Group | C |
What This Means for Your Garden
The dominant soil in Seattle, WA is Silty Loam soil. Loam is considered the gold standard for gardening. It holds moisture without getting soggy, provides good nutrient retention, and has a loose enough structure for roots to spread easily. Most vegetables, flowers, and fruit trees perform well in loamy conditions.
The pH in your area ranges from 5.2 - 6.0, which is classified as Moderately Acidic. Acidic soil works well for blueberries, potatoes, and azaleas. If you need to raise the pH for other crops, agricultural lime is the standard amendment.
Your USDA hardiness zone is 8b, meaning winter lows can reach around 15 degrees Fahrenheit. This determines which perennials, trees, and shrubs will survive winter in your area. Check the plant recommendations below for varieties suited to both your soil and climate.
Best Plants for Your Soil & Zone
These plants thrive in Silty Loam soil and USDA zone 8b.
Vegetables
Tomato
Sun: Full sun (6-8 hours)
Water: Regular, 1-2 inches/week
Spacing: 24-36 inches
Pepper
Sun: Full sun (6-8 hours)
Water: Regular, 1-2 inches/week
Spacing: 18-24 inches
Lettuce
Sun: Full sun to partial shade (4-6 hours)
Water: Regular, 1 inch/week; keep consistently moist
Spacing: 6-12 inches
Cucumber
Sun: Full sun (6-8 hours)
Water: Regular, 1-2 inches/week; consistent moisture critical
Spacing: 36-60 inches
Squash (Summer/Winter)
Sun: Full sun (6-8 hours)
Water: Regular, 1-2 inches/week
Spacing: 36-60 inches
Broccoli
Sun: Full sun (6-8 hours)
Water: Regular, 1-1.5 inches/week
Spacing: 18-24 inches
Cabbage
Sun: Full sun (6-8 hours)
Water: Regular, 1-1.5 inches/week
Spacing: 18-24 inches
Corn (Sweet)
Sun: Full sun (8+ hours)
Water: Regular, 1.5-2 inches/week; critical at tasseling
Spacing: 12-15 inches in blocks
Onion
Sun: Full sun (6-8 hours)
Water: Regular, 1 inch/week; reduce near harvest
Spacing: 4-6 inches
Garlic
Sun: Full sun (6-8 hours)
Water: Moderate, 0.5-1 inch/week; stop watering 2 weeks before harvest
Spacing: 6 inches
Spinach
Sun: Full sun to partial shade (4-6 hours)
Water: Regular, 1-1.5 inches/week
Spacing: 4-6 inches
Kale
Sun: Full sun to partial shade (4-8 hours)
Water: Regular, 1-1.5 inches/week
Spacing: 18-24 inches
Beet
Sun: Full sun to partial shade (4-8 hours)
Water: Regular, 1 inch/week
Spacing: 3-4 inches
Eggplant
Sun: Full sun (8+ hours)
Water: Regular, 1-2 inches/week
Spacing: 24-30 inches
Celery
Sun: Full sun to partial shade (4-6 hours)
Water: Heavy, 2+ inches/week; never let soil dry out
Spacing: 8-10 inches
Cauliflower
Sun: Full sun (6+ hours)
Water: Regular, 1-2 inches/week; consistent moisture critical
Spacing: 18-24 inches
Zucchini
Sun: Full sun (6-8 hours)
Water: Regular, 1-2 inches/week
Spacing: 36-48 inches
Pumpkin
Sun: Full sun (6-8 hours)
Water: Regular, 1-2 inches/week; reduce near harvest
Spacing: 60-96 inches
Fruits
Strawberry
Sun: Full sun (6-8 hours)
Water: Regular, 1-1.5 inches/week; drip irrigation preferred
Spacing: 12-18 inches
Raspberry
Sun: Full sun (6-8 hours)
Water: Regular, 1-1.5 inches/week
Spacing: 24-36 inches
Apple
Sun: Full sun (6-8 hours)
Water: Regular, 1 inch/week; deep watering preferred
Spacing: 15-25 feet (standard), 6-10 feet (dwarf)
Pear
Sun: Full sun (6-8 hours)
Water: Regular, 1 inch/week
Spacing: 15-20 feet (standard), 8-12 feet (dwarf)
Plum
Sun: Full sun (6-8 hours)
Water: Regular, 1 inch/week
Spacing: 15-20 feet (standard), 8-12 feet (dwarf)
Blackberry
Sun: Full sun (6-8 hours)
Water: Regular, 1-2 inches/week during fruiting
Spacing: 3-5 feet
Flowers
Rose
Sun: Full sun (6-8 hours)
Water: Regular, 1-2 inches/week; deep watering preferred
Spacing: 24-48 inches
Zinnia
Sun: Full sun (6-8 hours)
Water: Moderate, 1 inch/week; avoid overhead watering
Spacing: 6-18 inches
Dahlia
Sun: Full sun (6-8 hours)
Water: Regular, 1-2 inches/week
Spacing: 18-24 inches
Lily
Sun: Full sun to partial shade (6-8 hours)
Water: Regular, 1 inch/week; well-drained essential
Spacing: 8-12 inches
Hydrangea
Sun: Partial shade to full sun (4-6 hours)
Water: Regular, 1-2 inches/week; moisture loving
Spacing: 36-60 inches
Peony
Sun: Full sun (6-8 hours)
Water: Regular, 1 inch/week
Spacing: 36-48 inches
Iris
Sun: Full sun (6-8 hours)
Water: Low to moderate; good drainage essential
Spacing: 12-24 inches
Chrysanthemum
Sun: Full sun (6-8 hours)
Water: Regular, 1 inch/week; avoid wet foliage
Spacing: 18-24 inches
Herbs
Mint
Sun: Partial shade to full sun (3-6 hours)
Water: Regular, 1-2 inches/week; moisture loving
Spacing: 18-24 inches (container recommended)
Cilantro (Coriander)
Sun: Full sun to partial shade (4-6 hours)
Water: Regular, 1 inch/week
Spacing: 6-8 inches
Dill
Sun: Full sun (6-8 hours)
Water: Moderate, 1 inch/week
Spacing: 12-15 inches
Chives
Sun: Full sun to partial shade (4-8 hours)
Water: Regular, 1 inch/week
Spacing: 8-12 inches
Fennel
Sun: Full sun (6-8 hours)
Water: Regular, 1 inch/week
Spacing: 12-18 inches
Trees
Oak
Sun: Full sun (6-8 hours)
Water: Moderate; drought tolerant once established
Spacing: 30-50 feet
Maple
Sun: Full sun to partial shade (4-8 hours)
Water: Regular; consistent moisture preferred
Spacing: 25-45 feet
Dogwood
Sun: Partial shade to full sun (4-6 hours)
Water: Regular; consistent moisture preferred
Spacing: 15-25 feet
Magnolia
Sun: Full sun to partial shade (4-8 hours)
Water: Regular; consistent moisture preferred
Spacing: 20-40 feet
Willow
Sun: Full sun (6-8 hours)
Water: Heavy; thrives near water sources
Spacing: 30-50 feet
Elm
Sun: Full sun (6-8 hours)
Water: Moderate; tolerates some drought
Spacing: 40-60 feet
Cherry (Ornamental)
Sun: Full sun (6-8 hours)
Water: Regular, 1-2 inches/week
Spacing: 20-30 feet
Apple Tree
Sun: Full sun (6-8 hours)
Water: Regular, 1-2 inches/week
Spacing: 15-25 feet (standard), 6-10 feet (dwarf)
Pear Tree
Sun: Full sun (6-8 hours)
Water: Regular, 1 inch/week
Spacing: 15-20 feet (standard), 8-12 feet (dwarf)
Pecan
Sun: Full sun (8+ hours)
Water: Regular; deep watering preferred
Spacing: 40-60 feet
Walnut
Sun: Full sun (6-8 hours)
Water: Regular; deep roots access groundwater
Spacing: 40-60 feet
Shrubs
Boxwood
Sun: Partial shade to full sun (4-8 hours)
Water: Regular, 1 inch/week; consistent moisture
Spacing: 24-48 inches
Holly
Sun: Full sun to partial shade (4-8 hours)
Water: Regular, 1 inch/week
Spacing: 36-72 inches
Hydrangea
Sun: Partial shade to full sun (4-6 hours)
Water: Regular, 1-2 inches/week; moisture loving
Spacing: 36-72 inches
Forsythia
Sun: Full sun (6-8 hours)
Water: Moderate; tolerates some drought
Spacing: 48-72 inches
Privet
Sun: Full sun to partial shade (4-8 hours)
Water: Moderate; tolerates drought once established
Spacing: 24-48 inches (hedge), 60-96 inches (specimen)
Viburnum
Sun: Full sun to partial shade (4-8 hours)
Water: Regular, 1 inch/week
Spacing: 48-96 inches
Spirea
Sun: Full sun (6-8 hours)
Water: Moderate; tolerates some drought
Spacing: 36-60 inches
How to Improve Your Soil
Here are the top amendments recommended for Silty Loam soil:
- Compost — Improves structure and reduces erosion susceptibility
- Coarse Organic Mulch — Prevents crusting and erosion from rain impact
- Perlite — Improves drainage and reduces compaction
- Cover Crops (Annual Rye) — Root systems hold soil against erosion and improve structure
Nearby Areas
Frequently Asked Questions
What type of soil is in Seattle, WA (98101)?
98101 has Silty Loam soil based on USDA soil survey data. It is moderately well drained with a pH range of 5.2 - 6.0.
What USDA hardiness zone is 98101?
Seattle, WA (98101) is in USDA hardiness zone 8b, with minimum winter temperatures around 15 degrees Fahrenheit.
What grows well in Silty Loam soil?
Silty Loam soil works well for many common garden plants. Check the plant recommendations section above for vegetables, flowers, herbs, and trees that thrive in this soil type and zone 8b.
How do I improve Silty Loam soil for gardening?
The best approach is to add organic matter such as compost, aged manure, or leaf mold. See our full amendment guide for Silty Loam soil for step-by-step instructions.
Where does this soil data come from?
All soil data on MySoilType comes from the USDA Natural Resources Conservation Service (NRCS) Web Soil Survey, the most comprehensive source of soil information in the United States.