The bright orange to orange-red blossoms displayed on the trailing vines of goldfish plants (Columnea spp.) glow in the bright filtered light from a window. Native to Costa Rica, Columnea microcalyx is hardy in the warm, frost-free temperatures of U.S. Department of Agriculture plant hardiness zones 11 through 12; some other goldfish plants' hardiness range includes USDA zone 10. Normally grown as houseplants, goldfish plants thrive when planted in a loose, well-drained potting mix. They require relatively simple care when grown in a humid atmosphere with a temperature above 60 degrees Fahrenheit, ideally at 65 degrees Fahrenheit. Those conditions keep the plants green and lush.
Things You'll Need
- Watering device
- Warm- or cool-steam humidifier
- 15-15-15 liquid fertilizer
- Disposable teaspoon
- 1-gallon bucket or water bottle
- Dish-washing liquid
Place each goldfish plant's flowerpot or hanging basket in a location that receives at least 13 hours of bright filtered light or dappled sunlight daily.
Water the plants when the potting mix is nearly dry. Add enough water to wet the potting mix and drain from the bottom of the plants' flowerpots or other containers. Reduce watering in winter, when the plants' growth slows, to once every two to four weeks. Avoid overwatering. Otherwise, root rot may develop.
Keep the air around the goldfish plants humid by using a warm- or cool-steam humidifier. Misting with a spray bottle to provide humidity is inconsistent and less efficient than using a warm- or cool-steam humidifier.
Fertilize twice each month with a 15-15-15 liquid fertilizer solution when the plants grow actively. Mix 1/2 teaspoon of the fertilizer with 1 gallon of water, and pour the solution over the potting mix until it drips from the bottom of the plants' containers.
Remove dead blossoms and pinch back rapidly growing stems with your fingers as needed throughout the year. Cutting back dangling stems forces the plants to produce more stems, thickening the plants' growth.
Monitor the goldfish plants for pests such as aphids and whiteflies. Aphids are soft insects that may be green, yellow or other colors; they often are in large groups on tender new growth. Whiteflies are white and found on the undersides of leaves. Most pests can be removed easily either by rinsing the plants outdoors with a blast of water or by gently washing their leaves with a mixture of 1 gallon of water and two or three drops of dish-washing liquid over a sink.
Tips & Warnings
- Use spagnum moss or a mixture of equal portions of perlite, sphagnum moss and vermiculite when repotting goldfish plants. They are epiphytic plants, which means they do not require soil.
- Root cuttings or stems from pruning in a moist potting mix if you wish to propagate the plants.
- "Goldfish plant" is a common name also used for Nematanthus species, which have growing requirements similar to those of Columnea species. Nematanthus gregarius is hardy in USDA zones 14 through 15.
- Avoid touching the leaves of goldfish plants if you're a smoker. The tobacco mosaic virus may be transmitted to your plants from your fingers that touched a cigarette with affected tobacco. Once infected, the plants' leaves may be discolored and distorted. The virus has no cure.
- Avoid overwatering and getting water on the leaves of the plants. Goldfish plants are prone to molds and fungi infections when their leaves are wet for long periods of time. If white or gray mold spots appear, control the infection by quickly removing infected leaves and stems and putting them outside in the trash.
- Keep all fertilizers out of the reach of children and pets.
- Missouri Botanical Garden: Columnea Microcalyx
- Logee's Tropical Plants: Cultural Information -- Columnea
- North Dakota State University Extension Service: Hortiscope -- Questions on Goldfish Plants
- University of Vermont: Columnea
- University of California Integrated Pest Management Online: Aphids
- University of California Integrated Pest Management Online: Whiteflies
- University of California Integrated Pest Management Online: Tobacco Mosaic Virus
- Penn State Extension: Botrytis or Gray Mold