Have these plants been outside yet? If so, are they outside all the time, or just for a few hours a day?

Did you grow these plants from seed or purchase them from somewhere else?

The plants look pretty healthy overall. My first suggestion would be to look for wee pests, such as mites or whiteflies or aphids.

If the plants are outside all, or most, of the time: The spots could be caused by a bit of fungus that is encouraged by chilly wet weather. This should resolve once the weather warms up and dries out. In the meantime if you only have a few plants and they are in pots, you could move them indoors where they would be warmer and drier.