Dark Pepper Leaves

[AlittleSalt]

I potted peppers into solo cup earlier this week and set them out in the shade to get adjusted to the outside weather (I forget what this is called)

Anyway, the leaves are a very dark green. I took a picture but the color doesn't show true on the picture. I'm wondering why they are so dark now?

Details:
Started seeds in cells using pro mix.
Planted plants in solo cups using MG Potting Mix (Not the organic kind) - the one with flavor berries in the mix that feeds for up to 6 months.
It's hot here 90+F.
Pictured are Pasilla Bajio. Guajillo, and Chocolate Cherry Bomb

flavor berries