Backyard garden, Santa Monica, plenty of sunlight, no overhead watering.

Earlier this week I noticed some small stains on the leaves of my rainbow swiss chard (from seed). Thought nothing of it because it was about to come up anyway. Yesterday I look and find there are black lesions (roughly 3-4 inch long maybe 1/2 inch wide) on many of the leaves. I looked around my garden to find that similar spots had appeared on almost everything in it (nasturtiums, pasilla and thai pepper, pacific calendula, marigolds, buckwheat, pole beans, heavenly blue morning glories, savoy spinach). All but the peppers were grown from seed. The lesions appear slightly differently in each of the species. On the bean leaves, they are more blotchy and slimy, the pepper leaves have a black vertical lesion and are also slimy, the nasturtiums have some slimy residue all over in addition to the discoloration, the morning glories don't have the slime, but have black spots.

I thought at first it might be black rot, but it appears to have started on chard which isn't part of the cruciferae family. It hasn't affected most of my herbs, tomatoes, or the succulents in my garden. My kale didn't seem affected either (though there was a massive aphid outbreak on one of the plants which has been taken care of).

Any ideas, questions, or thoughts would be greatly appreciated.