There isn't a gardening vendor in MB, DS, or GH. The gardening vendors are in WC, KT, MS, and CS.
You have to be lvl 30 to get in Marleybone
If you are a paying member, you will first need to complete Krokatopia. Once you beat the queen, the dogs from Marlybone will take it so they can keep it safe in the Marlybone Museum. Once that happens, you will be granted a Marlybone spiral key which you can use to go to Marlybone.
Hammund Vittlecrafter is the Grizzleheim snack recipe vendor and is located in Ravenscar.
Mooshu has a pet vendor at Jade Palace that you can buy The Goat Monk from her.
When you hit level 12, Moolinda Woo (sorry if I made an error on her name), the life teacher, will contact you and from there you can follow the instructions to start gardening.
In Wizard101, the Avalon vendor can be found in the Avalon world, specifically in the area known as the "Castle Avalon." This vendor, often referred to as the "Avalon Gear Vendor," sells various gear and items themed around the Avalon storyline. Players can access this area after completing certain quests in the game. Be sure to explore the different zones within Avalon to find other vendors and treasures!
You can only get it from vendors in marlybone dragonspyre Mooshu and krokotopia. Annoyingly not in wizard city. (This is all I know at the moment there might be other ways of getting it)
To garden, you must be at least level 12. And then you have to complete the gardening quest.
When you are at level 15 you can move out of your dorm and buy a house or castle from a castle vendor in the spiral.
There is a bunch of people that pop up once a year Feburary -valintines day gear vendor March -ST paty's day vendor April -Easter vendor October- halloween gear vendor and Jack Hallow who gives Halloween quests November- thanksgiving gear vendor December- Winter gear
Roughly 30 to 35
marlybone