natural source of radioactive?

The only Natural nuclear energy sources in the universe are stars like our sun. There is no known plant material that will suck up fissile material and concentrate it for us.

Uranium is natural but rare. Most metals used in nuclear power are made from uranium, and it isn't a simple or cheap process. Nuclear power by fission is the most expensive way to boil water.

I think a cheap energy solution would lie with fusion--less deadly waste, no rare elements required, we just need to learn to harness it. A better solution would be to make a better battery, so that we can use the sun's constant nuclear power for energy needs.

No, you cannot grow it. You can mine uranium but it must be refined to use in a reacor which we already do. How would growing a nuke help? Methinks you don't understand basic nuclear physics.

if you have pitchblende on hand from a uranium mine you can get radium, polonium, thorium, etc. but only in minute quantitites. good luck with the FBI/ATF showing up at your house by the way