That's a first!
It may take some time for the plants to produce a seed. Are you seeing any seeds coming from the plants? Do the seeds produce new plants?
Viewing post in Alien Plants v1: Evolution simulation comments
I'm not updating this specific version anymore, but I released a new prototype. https://alejocamaleon.itch.io/alien-plants-team-seas Could you try this one instead and check this one works for you?