The prayer plant's (Maranta leuconeura) most striking and distinctive characteristic is its habit of closing its leaves at the end of the day. Each set of folded leaves takes on the appearance of praying hands, from which the plant gets its name. Because the prayer plant cannot tolerate any amount of cold, it is grown as a houseplant in all but a few areas.
The prayer plant is a low-growing plant native to Brazil. Emerging from a rhizomatous, or fleshy ,tuber-like root, it grows to roughly 12 inches tall and about as wide. Its oval leaves grow to 5 inches long and are mostly green but usually variegated with lines and areas of contrasting color. The bottoms of the leaves are grayish to purple-green, and small white flowers sometimes emerge on thin spikes. The plant's stems and leaves respond to light by opening early in the day and closing together in the evening.
As a strictly tropical plant, the prayer plant is only winter-hardy in U.S. Department of Agriculture plant hardiness zones 10b and 11a, as it cannot tolerate temperatures below freezing. In the continental United States, this comprises a very small area that includes the southernmost tips of Florida and California. Elsewhere, it is well-suited to the warm humid environment that a terrarium provides, as its maximum size at maturity does not take over.
Prayer plants do best in an environment that closely resembles their natural native habitat. Bright to moderate light with some shade, high humidity, consistently moderate temperatures of at least 60 degrees Fahrenheit, and moist, well-drained soil are key to its success. Avoid direct sunlight that can cause leaf colors to fade, and water less frequently from fall to late winter while the plant is dormant. If maintaining the proper humidity level is a problem, the Missouri Botanical Garden suggests placing the pot in a tray of wet pebbles.
Prayer plants are generally not bothered by diseases or insects, though you may occasionally see spider mites or mealy bugs on the leaves. A strong spray of cool water usually removes them without harming the plants, as the leaves actually enjoy an occasional shower. Leaving the plant in saturated soil too long may also cause root rot, which is easily remedied by allowing the soil to dry before watering again. Prayer plants are propagated by division, best done in early spring. Remove the plant from the pot and shake off as much soil as possible, then cut through the root between the stems. Repot the divisions in a medium made up of one part soil, two parts peat and 1/2 part sand, and place in indirect light.