Maricopa County, AZ Extension Office & Soil Testing Directory
Welcome to the official directory resource for Maricopa County, AZ. Connecting local homeowners, urban gardeners, and commercial growers with Arizona'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 Arizona Cooperative Extension - Maricopa County serves as the primary educational extension center in Maricopa County. Visit or call during standard operational hours for agricultural advice, soil sample kits, and youth 4-H programs.
| Official Office Name: | University of Arizona Cooperative Extension - Maricopa County |
| Physical Address: | 4341 E. Broadway Road, Phoenix, AZ 85040 |
| Direct Phone Desk: | (602) 827-8200 |
| Email Contact: | maricopaext@arizona.edu |
| Office Hours: | Monday – Friday: 8:00 AM – 5:00 PM |
| Official Web Portal: | https://extension.arizona.edu/maricopa |
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 Maricopa County is UA Certified Environmental Soil Laboratory Partner.
| Official Testing Lab: | UA Certified Environmental Soil Laboratory Partner |
| Lab Location: | 2515 N 27th Ave, Phoenix, AZ 85009 |
| Routine Sample Fee: | $25 desert salinity & pH sample kit |
| Expected Turnaround: | 7 to 10 business days |
| Official Lab Website: | https://extension.arizona.edu/maricopa |
How to Collect and Submit a Soil Sample in Maricopa County:
- Pick up a Soil Kit: Pick up official sample boxes and submittal forms at the University of Arizona Cooperative Extension - Maricopa County (4341 E. Broadway Road, Phoenix, AZ 85040).
- 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 UA Certified Environmental Soil Laboratory Partner.
3. Master Gardener Volunteer Program & Plant Clinic
The Maricopa County Master Gardeners provides free plant disease diagnostics, lawn care advice, and eco-friendly pest management tips.
| Program Name: | Maricopa County Master Gardeners |
| Plant Clinic Hours: | Monday – Friday: 9:00 AM – 12:00 PM (Note: Plant clinics run seasonally; call office during winter months) |
| Direct Helpline Phone: | (602) 827-8200 |
| Program Portal: | https://extension.arizona.edu/maricopamg |
Volunteer Training: 50 hours of UA desert horticulture instruction.
4. Regional Soil & Growing Snapshot for Maricopa County
USDA Plant Hardiness Zone: Zone 9b / 10a
Natural Soil Profile: Alkaline Sonoran Desert Caliche & Clay (pH 7.8 - 8.5)
Popular Local Crops: Citrus, dates, figs, peppers, desert legumes, bermudagrass
Extension Specialist Tip: Do not add lime to Arizona desert soils. Incorporate sulfur and compost to flush out excessive salts.
5. 🧮 Interactive Soil Amendment Calculator for Maricopa County
Estimate the recommended agricultural limestone or elemental sulfur needed to adjust your garden soil pH based on local Alkaline Sonoran Desert Caliche & Clay (pH 7.8 - 8.5) characteristics.
📚 Recommended Extension Guides & Soil Articles
Learn more about interpreting your Maricopa County extension soil test report and managing plant nutrients:
Frequently Asked Questions (Maricopa County Directory)
The University of Arizona Cooperative Extension - Maricopa County is located at 4341 E. Broadway Road, Phoenix, AZ 85040. You can call their main desk directly at (602) 827-8200 during standard business hours (Monday – Friday: 8:00 AM – 5:00 PM).
Standard soil analysis for Maricopa County garden samples through UA Certified Environmental Soil Laboratory Partner costs $25 desert salinity & pH sample kit. Check with the office for special sample types.
You can reach the Maricopa County Master Gardeners hotline by calling (602) 827-8200 during plant clinic hours (Monday – Friday: 9:00 AM – 12:00 PM).
Maricopa County falls primarily within USDA Plant Hardiness Zone 9b / 10a. Local soil is characterized as Alkaline Sonoran Desert Caliche & Clay (pH 7.8 - 8.5).
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.