I'll be honest, I've never played a cozy game before, and this left such a good impression I think I opened a gate! I spent a good half an hour to make sure to get the toxic levels down to 0 and it was SO satisfying to see everything turn from a muddy haze into fresh greenery. And those bubbles, so lovely, I felt like popping them through my screen!
A suggestion: Perhaps you could make it so that players can 'drag and drop' plants onto the screen? This would save them having to click to drop a plant, and then clicking again to drag the plant around.
Overall, very well done, thanks for making this game!