The most common and most likely answer to this crossword clue is the 6 letter word INSTIL
I've seen this crossword clue in The Guardian
I
N
S
T
I
L
More clues leading to the result INSTIL
- Drop in at home, even now not finished
- Cuckoo isn’t on middle of wild plant
- Drop this month’s import licences initially
- I love host street – drop in
- Implant not yet removed we hear
- Gradually introduce detailed steps to follow at home
- Introduce trendy source of booze — only one left
- Put in mind of elected list
- I love receiving next-door neighbours– drop in
- Impress trendy whisky-maker no end
Buddy explains!

The straight part
We know that "plant" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case plant = instil.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does INSTIL mean?
INSTIL verb- To cause a quality to become part of someone's nature.
- To pour in (medicine, for example) drop by drop.