Cooperative extension offices

University of Arizona Cooperative Extension

Tucson, Arizona, serving Arizona. Listed as a reference, not an endorsement.

Overview

The University of Arizona Cooperative Extension provides research based education and local resources through Arizona county offices. This listing is provided for reference, not as an endorsement, certification, ranking, or guarantee of current availability.

Services and programs

  • Horticulture education
  • County extension offices
  • Online publications

What to verify before you go

Contact the organization or review its official source before making a trip, placing an order, joining a garden, or applying for funding. Details that commonly change include:

  • County office contacts
  • Current classes and diagnostic services

Related directory resources

Browse all extension offices or return to the directory hub.

Sources and last verified

Source: University of Arizona Extension. Last checked 2026-10-04.

The University of Arizona Cooperative Extension connects Arizona residents with university education and local county resources. Its statewide source is a useful starting point when a gardening question depends on Arizona heat, soils, elevation, or water conditions.

What this listing covers

The published source identifies horticulture education, county extension offices, and online publications. County offices may be the best place to look for local contacts or services.

Before contacting an office

Check the county office page for current contacts, classes, and diagnostic services. Extension offerings vary by location, so this listing does not assume that every county provides the same service.

More tools

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Plan

Planting calendar

Build a schedule from your median last freeze date.

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Plan

Moon-phase planting calendar

Plan traditional garden tasks around the lunar phases.

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Plan

Seed starting calculator

Find the right time to start seeds indoors.

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Plan

Harvest date calculator

Estimate a harvest window from planting and maturity dates.

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Garden guides

Browse all guides

Greenhouse growing

Greenhouse temperature guide for seeds and seedlings

Use crop-specific greenhouse temperatures for seed germination, seedlings, frost protection, and ventilation, with practical day and night ranges.

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Diagram of a raised bed cross section showing timber walls, a layer of existing soil or coarse fill, and the measured depth of new soil being added.

Materials

How much soil does a raised bed need?

How to measure a raised bed and turn the volume into bags or bulk cubic yards, with a worked example for a common 8 by 4 bed.

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October calendar diagram showing planting windows for garlic, spring bulbs, hardy greens, and cover crops closing as the first fall frost approaches.

Seasonal

What can I plant right now in my garden?

In early October, most US gardeners can still plant garlic, spring bulbs, hardy greens, and cover crops. Here is what is still open and what has closed.

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Diagram of a tulip bulb in a soil cross section planted at about three times its own height, pointed end up, with a depth marker of 6 to 8 inches.

Fall planting

When should I plant tulip bulbs?

Plant tulip bulbs in fall, about 6 to 8 weeks before the ground freezes. Here is how the window shifts by region and how deep to plant.

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Plant library

Browse all plants
Illustration of a tomato plant stem with leaves and two round red fruits

Vegetable

Tomatoes

Warm-season plants with practical planting, spacing, sun, soil, and harvest guidance.

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Illustration of a pepper plant stem with leaves and one hanging bell pepper

Vegetable

Peppers

A guide to starting peppers, choosing a warm site, and keeping plants productive through summer.

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Illustration of a carrot root below the soil line with green fronds above

Vegetable

Carrots

Practical guidance for sowing carrots directly, preparing loose soil, and timing successive crops.

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Illustration of a lettuce head with layered rounded leaves

Vegetable

Lettuce

Cool-season planting and harvest guidance for crisp lettuce in beds and containers.

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Glossary terms

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plant labels

Annual

An annual is a plant that completes its life cycle from seed to flower and seed within one growing season. Learn how annuals differ from perennials and biennials.

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pests and diseases

Aphid

An aphid is a small sap-feeding insect that can cluster on young growth and spread plant viruses. Many aphids also have natural predators.

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plant biology

Apical dominance

Apical dominance is the tendency of a plant's main growing tip to suppress growth from buds lower on the stem and limit branching.

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pests and diseases

Beneficial insect

A beneficial insect helps a garden by pollinating flowers, eating pests, decomposing material, or supporting another useful ecological process.

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Gardening directories

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Cooperative extension offices

Colorado State University Extension

Colorado State University Extension connects Colorado residents with university education and county based gardening resources.

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Cooperative extension offices

NC State Extension horticulture

NC State Extension horticulture provides research based gardening and grower information connected to local county offices across North Carolina.

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Cooperative extension offices

Clemson Extension horticulture

Clemson Extension horticulture publishes home gardening and commercial horticulture information for South Carolina conditions.

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Nurseries and garden centers

American Native Plants

American Native Plants is a wholesale nursery and supplier listing native trees, shrubs, and perennials for professional buyers.

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