Make a list of about 40 threads that deal with micro-greens. Post it into this thread. One of the volunteer moderators might suddenly discover that they have unexpected free time, and decide to review them and add them into a new forum.
We can also add threads to multiple forums. I just added the one you mentioned, Michelle, to the Plants forum. You can also add threads to up to three forums if you have PIE. Here, I'll give you some and you can try it out.
And if you do find a bunch of thread about microgreens, like Joseph said, and add the links here, I or another moderator might be able to make a new forum, too