@RogueYumei The devs didn't use any mints^^ Conceal-mint worked quite well for me...you get more sun from the Moonflower, it gets rid of the zombies so Cauli can hypnotize Gargs and in addition you get scores for the helmets of the zombies.
I'm missing out on these mints on my mid level profile, too. I have to figure out a F2P mint-less strategy for my mid level profile tomorrow^^
Edit: Maybe not
Here a tip against the nasty pilot zombies: The first (I think) three waves of pilots don't land on C1 and C2. Only waves after that can go down on C1 and C2. So try to get a layout where Cauli is on C1, Moonflower on C2, and Shadow-Pea on C3. During the game you can dig up some MFs and replace them with Cauli.
I start with one Cauli and 10 MFs on C2 and C3. I replace the MFs on C3 with Shadow-Pea before the first pilots drop down. But I think you need Conceal-mint for that to work :/