It kind of depends on which Jesus.

Based on your disclosure, you are concerned with the cannonical depiction of Jesus. In which case what he was allegedly discussing with these two seeds parables were the growth of faith.

But as can be seen from 2 Cor 11, before the gospels are written there are other versions of Jesus floating around, and a number of the topics Paul writes about to Corinth in 1 Cor overlap with the group who thought Jesus was effectively citing Lucretius in his seed parables. You can even see that in 1 Cor 15 Paul refers to sown seeds in the context of the human body where he also talks about a first physical man vs a second spiritual man. It's only in 2 Cor that we see Paul talk about sown seeds relating to proselytizing.

This other extra-canonical group with ideas overlapping with early Corinth and their "other version of Jesus" had a very different eschatology from cannonical Christianity, and in their case they explained these parables as effectively relating to Greek atomism, but with the specific language of Lucretius. In fact, the apocryphal text they were following is filled with sayings of a Jesus very concerned with addressing the philosophical points of Leucretius in a rebuttal of the Epicurean belief there was nothing after death.

Essentially, there were at least two versions of Jesus in antiquity. One that was talking about evolution and matter being made of indivisible parts, and one that was not saying anything about this. The one that was canonized and a third of the world believes in today was the latter one, but personally I find the former a bit more astonishing coming from an age where these ideas were fringe and unconformable concepts but is now being read in an age where they are largely recognized as facts.

It actually reminds me of the structure of the third seed parable. That in the earlier age when they couldn't tell what ideas were wheat and which ideas were weeds it would have been better to have waited preserving both until such a time it was clear which ideas were wheat and which were weeds. But instead the church perhaps prematurely labeled this other tradition as weeds, it was banned on penalty of death to even possess, and we only know of it today from works buried and lost for millennia and only recently rediscovered.

(This too was an idea in Lucretius - that it would be a mistake to throw out explanations for things before knowing for sure what was correct.)