You will have to have done the first few steps of the game
This achievement involves a few steps to unlock a kitchen garden where you can grow vegetables.
Just below your home is an empty garden area with a sign which you read to start the quest. You will be directed to Horadric at The Dead Horse (the village tavern). When you speak to him, he will give you a Garden Certificate which you can use back at the sign to claim the garden.
Location of the sign and the kitchen garden
This should unlock the achievement, although the quest is not technically complete (you just need to find and talk to the Merchant).
More details are here