And then you’ll get lung cancer instead.

The problem with this whole idea, and any ideas for interstellar travel, is that the radiation levels outside the protection of our sun’s magnetosphere is just way too high. Any seeds or any organic matter would be destroyed by the time it reached another solar system even if it was frozen. Not to mention the fact that the radiation would thoroughly wreck most sensitive computing components in any computer or robot that you attempted to send that far. Why is this the case? Because to reach any potential colony in another solar system in a reasonable amount of time (even if “reasonable” is a few hundred years) we would have to have our colony ship travel at a certain percentage of the speed of light. At those speeds, even small amounts of radiation would be like bullets hitting the side of your ship. If a micro asteroid hits the ship… you can say goodbye to the whole colony ship.

TL,DR: Unless we develop sci-fi style energy shields then interstellar travel is a pipe dream.