| an exceptional aptitude for gardening or for growing plants successfully: Houseplants provide much pleasure for the city dweller with a green thumb. |

| green thumb n. An extraordinary ability to make plants grow well. |
A knack for growing plants and keeping them healthy: “All my houseplants are in sorry shape; it's clear I don't have a green thumb.”
green thumb
A knack for making plants grow well, as in Just look at Louise's plants
she really has a green thumb. This term presumably alludes to the stained fingers of an avid gardener. [First half of 1900s]