Would sending a concoction of bacteria that *could* survive, but probably won't. Could that help seed life just by providing some of the necessary building blocks.
We could take a capsule, freeze a bunch of biomass and send it to space on some sort of bullet powered by a radioactive materials so it just continues to build up slowly for years and years. Eventually it will hit a planet, the atmosphere will destroy the capsule releasing the lifeforms that might be broken into the raw ingredients to nucleates life.
By exploring the site of the meteor impact that killed the dinosaurs eventually we find an artifact that survived the impact. The artifact is covered with dna-type substance that could be the origins of life. A nucleator if you will. The catch, the artifact landed long after life began here.
Around this time it is realized that there is a possibility of the sowers checking on their plantation. Which sowers though, maybe that wasn't the first time earth was seeded.