Space plants about 18 inches apart in a garden that gets no more than a half day of sun. Plant them in groups for the biggest impact. Water them regularly, as they don't tolerate drought well. Once a month, feed them with a low-nitrogen fertilizer, or every week with a diluted liquid fertilizer. These plants are heavy feeders. Signs of underfeeding include yellowing leaves and weak stalks.
Space the plants tightly in the container. Check the soil regularly; never let it fully dry out. Fertilize weekly with a liquid fertilizer made for containers plants. Nutrients get leeched from the soil in containers quickly so regular fertilizing is essential. Place the containers in a semi-shaded area
You can also grow New Guinea Impatiens indoors. If cared for properly, they grow and bloom all winter. Place them in a location with bright light and at least a few hours of direct sunlight each day. Choose a container with good drainage. Keep the soil moist, but never soggy. Re-pot the plants in the spring if needed. For the summer months, give the indoor plants fewer hours of direct sunlight.