Duckweed fresh mulch update

A month ago, I did a little experiment when planting out tomato seedlings in my garden beds. I mulched a third of them with 2 to 3 inches of freshly harvested duckweed, an equal number of plants mulched with 2 to 3 inches of leaves, and the rest with no mulch. So far, the duckweed tomatoes and leaf mulched tomatoes are neck and neck for height, but the non-mulched tomatoes are 1/2 to 1/3 as high. Also, my duckweed mulched tomatoes have a decidedly darker green coloring than the leaf mulched, indicating a better nitrogen level. Will get pics asap.