Plant-Traders
plant-traders.co.uk
Online community of people sharing, swapping and selling plants, seeds, bulbs, and cuttings.
SeedSwappers.com
seedswappers.com
Free site for seed trading and swapping by seed swapper enthusiasts. Also has hints and tips on home gardening.
Dave's Garden: Trading
davesgarden.com
Registered members can enter have and want lists for plants and seeds, can search other members' lists, and keep track of active trades. Also trade forums, for paying members only.
Gardenpassion
gardenpassion.net
Seed trade site with searchable lists of varieties offered and sought, as well as tips on identification, seed collection, and storage.
Plant Internet Directory
plant.id.au
Allows the Australian public to list plants for sale and review listings from other gardeners.
World Plant Exchange
worldplantexchange.com
Offers free offers and requests for plant and seed traders worldwide.
Seeds from Bulgaria
geocities.com
Trader with an extensive list of seeds, including fruit trees, vegetables, ornamental trees and shrubs, and flowers. Also a list of wanted seeds.
GardenHere
gardenhere.com
Internet community and forum for trading landscape plants. Also some articles on garden and plant tips.
Gardenweb: Exchanges & Trading
forums.gardenweb.com
Members post their offerings and wants on the forums (various plant and seed categories), and can also maintain exchange lists in their member profile.