Dave's Garden 
Maintain plants and seeds inventory, discuss gardening, and trade seeds and plants with fellow gardeners. Many features are only available to paying members, some also to the general public.
http://davesgarden.com/I Can Garden 
Canadian gardening resource site by editor and Master Gardener, Donna Dawson. Includes a member's area, news, articles, book reviews, clubs, suppliers, pictures and links.
http://www.icangarden.com/
SeeMeGarden 
Community of gardening enthusiasts sharing tips, advice, experiences, and knowledge covering many aspects of gardening.
http://www.seemegarden.com/
The Helpful Gardener: Garden Forum 
A discussion forum for the home gardener. Members provide helpful answers for home gardening questions in a number of topics.
http://www.helpfulgardener.com/phpBB2/
GardenWeb 
Community of gardeners offering a wide range of resources. Forums on a large variety of general and specialized topics, glossary of botanical terms, seed exchange, and plant directory.
http://www.gardenweb.com/
Garden Country 
Message board for communing with other gardeners. Includes a butterfly garden guide, weed identifier, and e-cards.
http://www.gardencountry.com/
Garden Stew 
Discussion forums on several gardening topics, as well as a few home improvement topics.
http://www.gardenstew.com/
You Grow Girl 
Offers a young fresh twist on gardening information, tips and articles. Discussion forums and archives available.
http://www.yougrowgirl.com/
GardenWeb Australia 
Hosts forums, garden exchanges, articles, contests and a plant database.
http://www.au.gardenweb.com/
Blossom Swap 
Lively community of gardening enthusiasts, forums, plant and seed swaps, articles, gardening tips, and photographs.
http://www.blossomswap.com/
UKY Listserv: Gardens & Gardening 
Worldwide community chats via an e-mail mailing list on a wide variety of topics including gardening. Archives online available to members of the list.
http://lsv.uky.edu/archives/gardens.html
GardenBanter 
A web front to several usenet newsgroups, covering general, regional, and water gardening topics. Threads are displayed forum-style. Posting requires registering with the site.
http://www.gardenbanter.co.uk/
GardenBuddies.com 
Forums and photo galleries covering many gardening topics, visited by an international audience. Archives of plant information.
http://gardenbuddies.com
Gay Gardener 
Offers planting tips, gardening history, forums, quotes, and a monthly newsletter.
http://www.gaygardener.com
Homestead Garden 
Online community focused on gardening with a simplified-living bent. Forums, a few articles, links to extension services, and printable journals and logs.
http://www.homesteadgarden.com/
Just Gardeners 
Includes forums, articles, catalog reviews, and a plant and seed swap area.
http://justgardeners.com/
Hort.net: Archived Active Horticultural Mailing Lists 
Maintains archives of about 30 gardening-related mailing lists, with a link to archives of additional now defunct lists.
http://www.hort.net/lists/
Tinker's Gardens 
This site focuses on daylilies, providing articles on their cultivation and hybridization, as well as an database. Also provides discussions of some other flowers and vegetables. Most of the action is in the many forums.
http://www.tinkersgardens.com/
Northscaping 
Information resources, e-zine, forums, and links of interest to Northern gardeners and landscapers (USDA hardiness zones 1-5). Includes a landscape plant search, articles, climatic data, and business locators.
http://www.northscaping.com/
PlantTraders 
Online community of friends and gardeners, sharing experiences, plants, and seeds.
http://planttraders.ipbhost.com/
Rhen's Garden Club 
Christian gardening and homesteading site, offering forums, gardening information, and links to other resources.
http://www.freewebs.com/rhensgardenclub/
Gardeners at Witzend 
Family-friendly site offering gardening forums, members photo albums, and member-contributed links.
http://www.witzend.net/
Moosey's Country Garden Forums 
Discussion forums, garden journals and photo galleries, with topics including tours, plant identification, roses, and chat.
http://forums.mooseyscountrygarden.com/
Grows on You 
A free social network for gardeners that provides photo upload, gardening weblog and a feature to list plants.
http://www.growsonyou.com
Excuse the Weeds 
A forum and the ability to browse members' gardens. Listing new gardens is only available to paying members.
http://www.excusetheweeds.co.uk
Gardens Monthly Magazine. 
The website of Gardens Monthly magazine with an active forum for swapping ideas and solving problems.
http://www.gardening.co.uk
The Gardener's Forum 
A very active gardening forum with members from around the world.
http://www.agardenersforum.com
Ask an Arborist 
A forum for asking for advice on the care of trees, principally with a UK focus.
http://www.tree-care.info/ask
Garden World Discussions 
A friendly and knowledgeable community of gardeners, happy to share their experience with those new to gardening.
http://gardenworld.proboards103.com/index.cgi