Green’s Dictionary of Slang

1. (drugs) marijuana.

1976		R. Sabbag Snowblind (1978) 186: Rubia de la costa, the blonde from the coast, the finest, complete dynamite ‘up’ grass in the world. Take a hit.
2001		ONDCP Street Terms 3: Blonde — Marijuana.

2. (US black) a light. i.e. reduced alcohol content beer [despite the text, ‘the first light beer to see wide popularity’ was Miller Lite, launched in 1972 (wiki)].

2012

G. Pelecanos (con. 1972) What It Was 44: ‘Got some blondes behind your seat [...] Opener’s in the glove box.’ Jones retrieved a couple Miller High Lifes, golden in clear glass bottles.