Scant leaves on a regular basis -- is plant OK? (12)
I believe the answer is:
satisfactory
'ok?' is the definition.
(similar in meaning)
'scant leaves on a regular basis is plant' is the wordplay.
'leaves on a regular basis' indicates alternate letters (letters leave at regular intervals).
'plant' becomes 'factory'.
The alternating letters of 'scant' are 'sat'.
'sat'+'is'+'factory'='SATISFACTORY'
(Other definitions for satisfactory that I've seen before include "Acceptable - adequate" , "Fully acceptable" , "OK" , "unexceptional" , "fine" .)