Cooperative Extension Services
Although the emphasis in their publications is rural and agricultural, there are excellent resources in foods and nutrition, consumer education, family life, health and safety and horticulture that even city folk can use! Please be aware that the agricultural information is geared towards that state.
eXtension.org includes a Google Custom Search Engine that allows you to search 1008 Cooperative Extension Sites provided by 74 universities in the United States.
Home and Garden Information Center
The University of Maryland runs a call center to answer your plant and pest questions: Monday - Friday, 8 am - 1 pm (Eastern Time), 1-410-531-1757.
This website from the University of Illinois Extension includes a section on Selecting Trees for Your Home that can be used in the Pittsburgh region, as well as Composting for the Homeowner.
North Carolina State University: Horticulture on the Internet
A great effort to group cooperative extension horticultural publications by topic! But do be aware that the publications are from around the nation and do make sure you don't follow advice for Florida or California.
USDA Cooperative State Research, Education, and Extension Service
This is the government program which manages cooperative programs at state agricultural colleges.
Cooperative Extension in Allegheny County: Horticulture
Includes program information and various pamphlets from Penn State.
Penn State Cooperative Extension & Outreach
Some of their publications are available online in pdf format.
These are likely to have publications that are applicable to gardening in Pennsylvania.
Cornell University Gardening Resources
The New York extension service offers brochures on Vegetables, Flowers, Fruit, Lawn, Trees & shrubs, Houseplants, Weather & climate, Soil & composting, Pests, and Landscape planning.
Ohio State University Extension
Yard and Garden
Includes a huge collection of publications about the Home, Yard, and Garden, including cold frame construction, poison ivy identification, overwintering plants, controlling wildlife, composting, lawn care, information on specific plants such as raspberries, blueberries, grapes, strawberries, apples, wisteria, clematis, hardy kiwi, asparagus, cucumbers, lettuce, garlic, and mushrooms.
- Yard and Garden
PlantFacts has merged several digital collections developed at Ohio State University to become an international knowledge bank and multimedia learning center.
West Virginia University Extension Service
Last updated October 19, 2012