My novel Semiosis is set on a distant planet called Pax where iron is a scarce element in the planetary crust. But plants need iron, so some of the plants on that planet find ways to hunt and kill animals, which are a rich source of iron. This becomes a problem for the humans who arrive to colonize Pax.
Here on Earth, iron is a common element in the surface in most places — but the soil in flowerpots can become depleted. I’m taking no chances. This is the label of the plant food I give to my houseplants. They get all the iron they need, and I can sleep soundly.
Semiosis 