The most common and most likely answer to this crossword clue is the 6 letter word POLLEN
I've seen this crossword clue in The Daily Telegraph
P
O
L
L
E
N
Buddy explains!
The straight part
We know that "this helps growth" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case this helps growth = pollen.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 POLLEN mean?
POLLEN noun- A fine granular substance produced in flowers. Technically a collective term for pollen grains (microspores) produced in the anthers of flowering plants. (This specific usage dating from mid 18th century.)
- Fine powder in general, fine flour. (16th-century usage documented by the OED.)
- To cover with, or as if with, pollen.