San Joaquin County, CA Extension Office & Soil Testing Directory
Welcome to the official directory resource for San Joaquin County, CA. Connecting local homeowners, urban gardeners, and commercial growers with California's land-grant university extension resources, state soil testing lab services, and Master Gardener volunteer clinics.
1. Extension Office Contact Details & Operational Hours
The University of California (UC ANR) Extension - San Joaquin County serves as the primary educational extension center in San Joaquin County. Visit or call during standard operational hours for agricultural advice, soil sample kits, and youth 4-H programs.
| Official Office Name: | University of California (UC ANR) Extension - San Joaquin County |
| Physical Address: | Stockton, California 95202 |
| Direct Phone Desk: | (060) 555-0199 |
| Email Contact: | san-joaquin@ucanr.edu |
| Office Hours: | Monday – Friday: 8:00 AM – 4:30 PM |
| Official Web Portal: | https://anlab.ucdavis.edu/ |
2. Official Soil Testing Laboratory & Pricing
Testing your soil is the single most important step before adding fertilizers or agricultural lime. The official testing laboratory serving San Joaquin County is UC Davis Analytical Laboratory.
| Official Testing Lab: | UC Davis Analytical Laboratory |
| Lab Location: | One Shields Ave, Hoagland Hall, Davis, CA 95616 |
| Routine Sample Fee: | $20 routine soil fertility analysis |
| Expected Turnaround: | 7 to 10 business days |
| Official Lab Website: | https://anlab.ucdavis.edu/ |
How to Collect and Submit a Soil Sample in San Joaquin County:
- Pick up a Soil Kit: Pick up official sample boxes and submittal forms at the University of California (UC ANR) Extension - San Joaquin County (Stockton, California 95202).
- Collect Sub-Samples: Use a clean stainless steel trowel to take 10 to 12 soil cores from a 4-to-6-inch depth across your garden or lawn area.
- Air-Dry: Mix sub-samples in a clean plastic bucket and air-dry on clean paper at room temperature (never use an oven).
- Submit Sample: Return your filled soil box to the extension office or mail directly to UC Davis Analytical Laboratory.
3. Master Gardener Volunteer Program & Plant Clinic
The San Joaquin County Extension Master Gardener Volunteers provides free plant disease diagnostics, lawn care advice, and eco-friendly pest management tips.
| Program Name: | San Joaquin County Extension Master Gardener Volunteers |
| Plant Clinic Hours: | Tuesday & Thursday: 9:00 AM – 12:00 PM (Note: Plant clinics run seasonally; call office during winter months) |
| Direct Helpline Phone: | (060) 555-0199 |
| Program Portal: | https://anlab.ucdavis.edu/ |
Volunteer Training: Comprehensive horticulture training conducted by University of California (UC ANR) Extension.
4. Regional Soil & Growing Snapshot for San Joaquin County
USDA Plant Hardiness Zone: Zone 8b / 10b
Natural Soil Profile: Central Valley Alluvial Silt Loam & Coastal Clay
Popular Local Crops: Tomatoes, citrus, figs, avocados, stone fruit, cool-season greens
Extension Specialist Tip: California soils benefit from organic mulch to reduce summer evaporative water loss and manage salinity.
5. 🧮 Interactive Soil Amendment Calculator for San Joaquin County
Estimate the recommended agricultural limestone or elemental sulfur needed to adjust your garden soil pH based on local Central Valley Alluvial Silt Loam & Coastal Clay characteristics.
📚 Recommended Extension Guides & Soil Articles
Learn more about interpreting your San Joaquin County extension soil test report and managing plant nutrients:
📦 Recommended Mail-In Soil Test Kits & Meters
FTC Affiliate Disclosure: We may earn a commissionIf you need immediate results without waiting for university mail-in lab turnaround times, these top-rated professional home soil test kits provide fast pH, N, P, and K diagnostic analysis:
MySoil Soil Test Kit
Professional mail-in kit analyzed by accredited labs. Returns 13 essential nutrient values (N, P, K, pH, Micronutrients) & customized fertilizer recommendations via app.
Luster Leaf Rapitest 1601
Popular color-comparator kit for 10 instant soil tests (pH, Nitrogen, Phosphorus, Potash). Includes tailored plant preference chart.
Sonkir 3-in-1 Soil Tester
Instant probe sensor for soil moisture, pH, and sunlight levels. Requires no batteries. Perfect for potted plants, lawns, and raised beds.
📋 Request Local Extension & Lawn Testing Assistance in San Joaquin County, CA
Need help interpreting your lab results or finding local agricultural extension agents? Fill out the brief form below:
Frequently Asked Questions (San Joaquin County Directory)
The University of California (UC ANR) Extension - San Joaquin County is located at Stockton, California 95202. You can call their main desk directly at (060) 555-0199 during standard business hours (Monday – Friday: 8:00 AM – 4:30 PM).
Standard soil analysis for San Joaquin County garden samples through UC Davis Analytical Laboratory costs $20 routine soil fertility analysis. Check with the office for special sample types.
You can reach the San Joaquin County Extension Master Gardener Volunteers hotline by calling (060) 555-0199 during plant clinic hours (Tuesday & Thursday: 9:00 AM – 12:00 PM).
San Joaquin County falls primarily within USDA Plant Hardiness Zone 8b / 10b. Local soil is characterized as Central Valley Alluvial Silt Loam & Coastal Clay.
Written & Verified by Sahajul
Verified Author & Founder
Sahajul is an independent agricultural data researcher based in India and founder of LocalSoilLab.com. He specializes in compiling, structuring, and verifying US land-grant university extension services, soil lab testing fee schedules, and county Master Gardener contact directories directly from official .edu and USDA NIFA portals.