Yeah, certainly not on private property, that is just wrong. Thats where the necessity of aome communication comes in. There has to be SOME rules,otherwise some jackass will think its a good idea to seed up a school or something. This is the tricky part...
It would have to be done at the right time. It would make the most sense to do it as a statement to directly oppose a "resurgance" from our opposition. Say, for example, there is a state enforced reversal of the current pro-medical movement, that would be a great time to execute. If, god forbid, some radicals get elected and start to increase their enforcement of marijuana.
In the mean time, just prepare the fort so to speak. Spread the word so people can prepare, so that when the bell rings people will be ready. If people went out of their way just a little to build up a good amount of seeds, it would really go a long way. If its a year from now, or 3, if everyone interested had a jarfull of seeds to deploy at a moments notice, then you just have to wait for a spark for it to catch