A Master Gardeners’ recommendations are made only after consulting research-based information. Oregon State University’s premier Horticulture program is the first check when addressing a gardening question. Below are links to many of the authorities used when addressing home horticulture questions.

General Gardening Questions
- OSU Extension Website – General Gardening Articles
- OSU Extension Publications Catalogs
- CoCRaHS Climate Guide:
- CoCoRaHS is a non-profit out of Colorado State University. Over 3000 volunteers across North America measure and report rain on a daily basis. The data is used by the National Weather Service and other scientists for a variety of research projects and is part of a growing data base. The CoCoRaHS site has a lot of precipitation data and some good links for the curious gardening mind. This link is a good introduction to the role of climate in gardening, with the Master Gardener in mind.

Plant & Weed Identification
- OSU Broadleaf Plant Search
- Common Trees of the Pacific Northwest
- Weed Identification (University of California)
- Weed ID Gallery (University of California

Insect & Spider ID
- PNW Pest Managment Handbooks
- Washington State University HortSense
- UC IPM (home garden, turf and landscape pests)
Pesticide Resources