Space might be an extreme example, but cramped, dark dwellings exist ... In Levine’s experiments on Earth, red light worked well for the slender flowering plants Arabidopsis.

It's especially important to have plants with colorful ... gazillions of coral bells with red foliage to choose from. This one grows to about a foot tall with dark purple almost black foliage.

Growing these plants in full sun will cause their branches and twigs to turn dark red, a nice contrast against their dark green, waxy leaves. In the summer, they bloom with slightly fragrant white ...

Ever since then, the festive plant that decorates our houses during the winter has earned a dark reputation ... chemical can be found in their bright red leaves. Predominant in teas, wines ...

But even longtime residents might be surprised to know that their dark red clusters of berries are ... Eastern spice blend of za’atar. The plant has many traditional medicinal uses, as well.