Forums in Gardening

1. LawnSite
LawnSite™ is the largest and most active online forum serving green industry professionals.
http://www.lawnsite.com/  

2. CactiGuide.com
Forum has 382,712 posts.
https://cactiguide.com/forum/  

3. GardenStew
GardenStew is a friendly community for gardeners and home owners featuring active forums, blogs, plant database, simple photo upload and more!
http://www.gardenstew.com/  

4. IDigMyGarden Forums
Forum has 988,693 posts.
http://idigmygarden.com/forums/  

5. TerraForums Venus Flytrap, Nepenthes, Drosera and more talk
Venus flytrap care Nepenthes Pinguicula Drosera and more forums as well.
http://www.terraforums.com/  

6. CactusWorld
The Online Community for Cactus and Succulent Growers
http://www.bcss.org.uk/foruma/  

7. Permaculture Forums from the P
Permaculture News, Information, Forums, Courses and Worldwide Reports
http://forums.permaculturenews.org/  

8. Seed Savers Exchange
Seed Savers Exchange is a non-profit organization of gardeners who save and share heirloom seed. Learn more about us and our mission - visit www.seedsavers.org for more info.
http://forums.seedsavers.org/  

9. Irish Gardening Forum for Irel
Forum has 10,523 members.
http://www.gardenplansireland.com/forum/  

10. Cactus Cultivars
Cactus Cultivars - Index
http://www.cactuscultivars.com/forum/  

11. Home Orchard Society Forums
Forum has 9,989 posts.
https://www.homeorchardsociety.org/forums/  

12. Arbtalk discussion forum for Arborists
https://arbtalk.co.uk/forums/