I'm not sure if this was planned or purely coincidental but many of the track names from the show this particular week make reference to the sacred herb.  
Perhaps it's just the nature of the music and it's proponents.
Twilight Circus Dub Sound System - Acetate
Linvall Thompson - Marijuana Dub
Lee Perry - Bushweed Corntrash
Michael Palmer - Smoke the Weed
Sly & Robbie - The Monkey is a Spy
Eek A Mouse - Ganja Smuggling
UB40 - Legalize it
Patrick Andy - Tired Fi Lick Weed in a Bush
Macka B - Legalize Herb
Junior Murvin - Bad Weed
Prince Far I - Commandment of Drugs
Augustus Pablo - Road Block
Jah Lion - Columbian Collie
Mossman - Funky Manifesto
The Upsetters - Word a Mouth dub
Audio Active - Free the Marijuana
Two Badcard - Weed Specialist
Dubaddxx - Hannibal's Journey
Century 800 - Changing Dub
Mad Professor - Boombox dub
Hyslop - Hypno Tricks
Cornell Campbell - 100 Lbs of Collie
Alkaline - Headlights
Black Uhuru - Natural Dub
Black Uhuru - Let us Dub
Black Uhuru - Convoy Hijack
Little Axe - Dark as night, cold as ground