I looked this up this morning but thought a more bilingual person might be able to help because what I found was contradictory. The "books" say "jogar verde" and "plantar verde para colher maduro" mean the same thing, but the English translations vary.
A Dictionary of Informal Brazilian Portuguese has:
Jogar verde: to bait the hook, ask leading questions
(same as "plantar verde para colher maduro")
Michaelis has the above, with an "o": "plantar verde para colher o maduro" and says it means "to beat around the bush" – definitely something different.
So I got confused. I'm sure now it is used in the baiting/questioning sense, like Johannes and Andre' wrote, not this beating around the bush sense. The context would help.
The sample sentence from "Informal Br Portuguese" is:
Não caio nessa, que você está plantando verde para colher maduro.
It almost sounds like setting a trap (armar a armadilha) but usually not in a serious situation. To bait the hook can mean this also (doesn't have to mean an actual worm, p.e., on a hook to catch a fish – note the article "the" is used not "a" – that's how you can tell).
I think the Michaelis definition is incorrect and don't know where it could have originated.
Here's what Houiass (Portuguese) says for "locuções under "verde":
m.q. plantar verde para colher maduro
plantar v. para colher maduro
sondar habilmente alguém, dizendo algo que provoque uma confissão ou uma informação que não conseguiria com uma indagação franca; jogar verde
Hope this helps :)
Abraços a todos,