How to Grow and Care for Croton Plants
The croton plant (Codiaeum variegatum) has colorful variegated foliage and nearly limitless leaf forms. As evergreens in USDA hardiness zones 11 and 12, they are often grown outdoors as ornamental shrubs. In their native habitat, crotons like humid, warm conditions with dappled light and plentiful water. These plants are difficult to please indoors. Outdoor plants can reach 10 feet in height, but pot-grown specimens tend to be much smaller, making them suitable for permanent houseplants or indoor/outdoor container plants. Generally, croton grows relatively slowly, gaining less than 12 inches of height per growing season.
When growing croton plants indoors, the primary challenge is maintaining the ideal temperature because if it is too cold, they start losing leaves. However, crotons are well worth the effort for their explosion of color. Croton can be planted any time of year, depending entirely on the temperatures remaining consistently 70 to 80 degrees Fahrenheit indoors, outdoors, or in a greenhouse. Crotons are toxic to humans and animals.
A well-grown croton keeps its leaves down to the soil level—and the trick to this is to provide steady warmth. Even in outdoor settings, crotons drop leaves after a cold night. Vibrant leaf colors depend on the quality of light; they need lots of bright, shifting sunlight.
Low humidity inside the house makes crotons particularly susceptible to spider mites. Mist the plants daily to avoid an infestation. Crotons can be brought outdoors when temperatures remain above 50 F, provided they are properly acclimated to the light and temperature conditions.
Crotons need bright, indirect light. Some may not tolerate unfiltered, direct sunlight and tend to thrive in dappled sunlight. Vibrant colors depend on if it gets sufficient bright light. If the plant lacks the light it requires, the leaves will turn green.
A well-drained, moist soil that has been enriched with compost is ideal. This plant prefers humus-rich, acidic soil.
Keep them evenly moist in the summer. Croton plants need about one inch of water per week. Reduce watering in the winter to biweekly. Watch the plant for signs that it needs more water, such as wilting young foliage. Increase watering if the wilting noticeably happens during hot weather, but check the top couple of inches of soil with a finger for moisture before you increase water. If it's still moist, hold off on watering. Mist frequently during the growth period.
Temperature and Humidity
Keep the room above 60 degrees Fahrenheit, and do not expose the plant to cold drafts. Humidity, along with the lack of bright light, also affects the color of the leaves. Keep the humidity level at 40 to 80 percent. If the humidity isn't high enough, the plant may drop some of its leaves. If you have trouble maintaining the moisture in your home at this level, run a humidifier in the room or set a humidity tray beneath the plant and group it with other plants.
Apply slow-release pellets three times per growing season: early spring, mid-summer, and early fall. Or, you can use a liquid fertilizer every other month during the growing season from early March to the end of September. Since fertilizers vary widely by type, read the package instructions for feeding quantity. In most cases, if you intend to feed on a regular schedule, you can reduce the package-suggested amount by half strength. Then, observe the plant's growth rate over the next month; you can adjust and add or reduce fertilizer depending on how vigorous you want your plants to grow. Stop giving fertilizer during the winter months.
Since this plant prefers slightly acidic soil, use acidifying fertilizers that contain ammonium nitrate, ammonium sulfate, or sulfur-coated urea. Your best target NPK ratios are 3-1-2 and 8-2-10 (nitrogen-phosphorus-potassium).