Although the plant is usually grown as a houseplant, it grows outdoors in the warm climates of USDA hardiness zones 10 through 12. Because of their small bushy rosette appearance they are best suited when grown outdoors as a ground cover or grouped together with other plants indoors.
Soil
This plant is well suited for planting in containers or hanging baskets. Drainage is critical, so make sure the container has a drainage hole in the bottom. Peperomia grows in any good-quality, regular commercial potting soil or a homemade mixture containing ingredients such as compost, loam or peat moss. A handful of sand or vermiculite promotes drainage.
Light
Watermelon Peperomia thrives in bright, indirect sunlight. Although most types of Peperomia thrive in bright light, too much light fades the bright colors of the variegated foliage. Indoors, a window with an eastern exposure provides excellent light. Outdoors, grow the plant in light shade or filtered light.
Water
Water the plant deeply when the top of the soil feels slightly dry. Let the pot drain completely and never allow the plant to stand in water. Check outdoor plants daily during warm weather. In fall and winter, water sparingly and allow more time between each watering so the soil has time to dry a bit more than usual. If the air is dry in summer, increase humidity by setting the container on a humidity tray.
Temperature
Watermelon Peperomia does not tolerate freezing temperatures. If you take your plant outdoors during warm weather, bring it in as soon as nighttime temperatures drop to 60 to 65 °F (15 to 18 °C). Ideal temperatures for the plant are 85°F (30°C) during the day and the low 60s °F (15°C) at night. Although the plant tolerates cooler weather, it will drop its leaves when temperatures drop below 50°F (10°C).
Fertilizer
Fertilize the Watermelon Peperomia once a month during spring and summer, using a balanced, water-soluble fertilizer. Avoid granular fertilizers, which are too strong and may scorch the plant. Watermelon Peperomia is a light feeder and too many nutrients may cause excessive growth and a leggy, spindly plant instead of a compact, bushy plant.
Propagation
Propagating a Watermelon Peperomia by leaf cutting is the most simple and efficient way to multiple your plant.
Source: sfgate.com
