Petra croton

One of my favorite indoor-outdoor plants is Codiaeum variegatum, commonly known as croton or Petra croton.

This colorful, leaved plant is native to Malaysia and the Pacific, which accounts for the fact that although it can thrive outdoors in summer and early fall, it is not able to handle frost or temperatures much below 60 degrees. Even when planted in the ground, freezing temperatures will not only kill the foliage, but the roots as well.

I keep my croton as a container plant. It’s glossy, brilliantly colored leaves of yellow, green, pink, orange, crimson and purple bring vibrant color to the outdoor garden, and when the temps start to drop, it is a perky addition to the indoors.

This common croton, along with other brightly colored cultivars, requires bright light both indoors and out, preferring not to have direct sunlight, which can fade leaf color. When light conditions are too low, croton will start to lose their lower leaves.

Leaf drop is common for croton, as it doesn’t like to be moved. Each year, when I bring my girl inside, she shrugs off some of her foliage in rebellion of the act. It is also a common occurrence when transported from the nursery to your home. It’s alarming at first, but take comfort in the fact she will come back around and sprout new foliage in no time with proper care.

Water croton thoroughly. Once the top of the soil is dry to the touch, water and keep watering until the water flows out of the bottom of the container. It should be kept away from drafts and cold, as that will also lead to the loss of leaves. Being tropical, it grows best in humid conditions.

Providing humidity to houseplants

It’s not easy to determine the humidity level of your home without a hygrometer, which measures the moisture level inside your home. It’s not a common gadget to own, but you will know to provide some humidity for your indoor plants if you see your plants exhibit signs of stress.

Indoor home conditions rarely duplicate the humidity levels of the great outdoors or a greenhouse. Instead, homes generally have a drier heat, especially when home heaters are on in winter. Leaves that develop brown edges or curl and plants that begin to wilt are commonly suffering from low humidity.

I have a “smart” heating and cooling system. It actually removes humidity from my home. Although energy efficient, the plants don’t like it — in summer or winter. However, there are ways to raise humidity levels in your home so that your plants can enjoy a healthier environment.

Plants can be lightly misted with room-temperature water using a spray bottle set to a fine mist. Leaves should look like they have a fine morning dew on them but are not beading or dripping with water. This also helps to clean leaves and discourages pests such as spider mites.

Place plants in a humidity tray. This can be a bowl or shallow pan with a layer of stones or pebbles at the bottom with water added, making sure the water stops just below the top of the stones. Plants should not be placed directly into water, as this could cause root rot. Plants are placed on top of the stones, and the water will create humidity.

Transpiration — defined as the process of water being absorbed through the roots, traveling up the stem and water vapor being released from the leaf — also helps to create a humid environment, especially when plants are grouped together. The water vapor creates humidity, and having the plants grouped together helps to contain the moisture between the plants.

If all else fails and you don’t seem to be getting the humidity levels that your plants require, the next step would be a humidifier. It doesn’t matter if it is a cool-air or warm-air humidifier, as long as you clean it regularly and allow for proper airflow to alleviate moisture to sit on your plants which could lead to a fungal or other disease.

Until next week, happy gardening.

— Irland, a member of the Limestone County Master Gardeners, can be reached at kippirland@hotmail.com. For more information on the Limestone County Master Gardeners, visit http://mg.aces.edu/limestone.