In one of the solar systems I've created for my fictional universe, there is a small planet within the habitable zone between the size of Mercury and Venus. It's an incredibly rocky planet, with high quantities of minerals. The sun in that solar system is smaller than ours, so the climate on this planet is rather cold, and there's very little water to be found, though it's not completely devoid of it.
Most of the planet is a cold rocky desert, though there are some areas with soil eroded from the surrounding landscape. The planet has a lot of iron--making the soil a reddish colour, I believe?-- and other metals, mostly alkaline (sodium, calcium, magnesuim, etc.). There isn't much organic matter in the dirt, but there is enough to sustain some amount of recurring life. From what I do know about how the climate would affect the plants, I know there wouldn't be many tall or large plants, it would mostly be shubbery and short grass.
At some point, humans land on this planet to explore, and take note of what plant life would be edible. Mostly, what I'm trying to figure out is, how would the soil composition affect the taste of these plants? I'm assuming most would be very bitter due to the climate, but I'm wondering if the type of soil would in any way affect how they would taste, or maybe even grow.
Also, if possible, I'd like to know some examples of plants on Earth in similar environments, to help me create more diversity within the flora than just bushes and grass. Ones considered edible would be especially helpful.