Green’s Dictionary of Slang

1. (Irish) the vagina.

c.1804

‘McClure’s Ramble’ in A. Carpenter Verse in Eng. in 18C Ireland (1998) 502: I wrought her plantation with good cultivation around, / But I could not well tarry to see her wheat harvest cut down.

2. (US und.) a prison.

1998

Austin American-Statesman (TX) 4 Oct. 9/4: Texas Prison gang Slang [...] Plantation: Prison.