San Diego County, CA Extension Office & Soil Testing Directory
Welcome to the official directory resource for San Diego 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 UC Cooperative Extension - San Diego County serves as the primary educational extension center in San Diego County. Visit or call during standard operational hours for agricultural advice, soil sample kits, and youth 4-H programs.
| Official Office Name: | UC Cooperative Extension - San Diego County |
| Physical Address: | 9335 Hazard Way, Suite 201, San Diego, CA 92123 |
| Direct Phone Desk: | (858) 822-7711 |
| Email Contact: | cesandiego@ucanr.edu |
| Office Hours: | Monday – Friday: 8:00 AM – 5:00 PM |
| Official Web Portal: | https://cesandiego.ucanr.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 Diego County is UC Davis Analytical Laboratory & Local Partner Labs.
| Official Testing Lab: | UC Davis Analytical Laboratory & Local Partner Labs |
| Lab Location: | One Shields Ave, Davis, CA 95616 |
| Routine Sample Fee: | $20 per routine soil sample |
| Expected Turnaround: | 7 to 10 business days |
| Official Lab Website: | https://anlab.ucdavis.edu/ |
How to Collect and Submit a Soil Sample in San Diego County:
- Pick up a Soil Kit: Pick up official sample boxes and submittal forms at the UC Cooperative Extension - San Diego County (9335 Hazard Way, Suite 201, San Diego, CA 92123).
- 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 & Local Partner Labs.
3. Master Gardener Volunteer Program & Plant Clinic
The Master Gardener Association of San Diego County provides free plant disease diagnostics, lawn care advice, and eco-friendly pest management tips.
| Program Name: | Master Gardener Association of San Diego County |
| Plant Clinic Hours: | Monday – Friday: 9:00 AM – 3:00 PM (Note: Plant clinics run seasonally; call office during winter months) |
| Direct Helpline Phone: | (858) 822-7711 |
| Program Portal: | https://www.mastergardenersd.org/ |
Volunteer Training: UC ANR 50-hour horticultural training.
4. Regional Soil & Growing Snapshot for San Diego County
USDA Plant Hardiness Zone: Zone 10a / 10b
Natural Soil Profile: Decomposed Granite Sandy Loam (pH 6.5 - 7.2)
Popular Local Crops: Avocados, citrus, succulents, protea, tomatoes
Extension Specialist Tip: San Diego decomposed granite soil drains quickly; add organic compost to hold water.
5. 🧮 Interactive Soil Amendment Calculator for San Diego County
Estimate the recommended agricultural limestone or elemental sulfur needed to adjust your garden soil pH based on local Decomposed Granite Sandy Loam (pH 6.5 - 7.2) characteristics.
📚 Recommended Extension Guides & Soil Articles
Learn more about interpreting your San Diego County extension soil test report and managing plant nutrients:
Frequently Asked Questions (San Diego County Directory)
The UC Cooperative Extension - San Diego County is located at 9335 Hazard Way, Suite 201, San Diego, CA 92123. You can call their main desk directly at (858) 822-7711 during standard business hours (Monday – Friday: 8:00 AM – 5:00 PM).
Standard soil analysis for San Diego County garden samples through UC Davis Analytical Laboratory & Local Partner Labs costs $20 per routine soil sample. Check with the office for special sample types.
You can reach the Master Gardener Association of San Diego County hotline by calling (858) 822-7711 during plant clinic hours (Monday – Friday: 9:00 AM – 3:00 PM).
San Diego County falls primarily within USDA Plant Hardiness Zone 10a / 10b. Local soil is characterized as Decomposed Granite Sandy Loam (pH 6.5 - 7.2).
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.