What does the cryptic crossword clue "Cabbage or turnip as carbs? I must need correcting (8)" mean?

The definition is "Cab". The wordplay uses an anagram. anagram of AS + CARBS? + I = BRASSICA; definition: "Cabbage" The answer is BRASSICA.

Cabbage or turnip as carbs? I must need correcting (8)

Guardian Cryptic #29339 | 18 Across | 2024-03-25 flower