Green’s Dictionary of Slang

cabbage patch n.¹

the vagina.

1890–1904		Farmer & Henley Sl. and Its Analogues.
c.1904		A. Crowley Snowdrops from a Curate’s Garden 25: Gertie and Herminia seized each one of his shoulderblades in their gaping cabbage-fields.
1980		Maledicta IV:2 (Winter) 193: The third and most numerous group of fruit and vegetable synonyms comes from analogy with the corresponding feminine terms, so that the gardener tends the garden or cabbage patch.