General Foliage Plant Care
Indoor plants are usually native to tropical areas of the world, and need light, moisture, and temperatures similar to that of their native environment. The following care-guide is designed to assist you in determining which plants would do best in your indoor environment and then how to care for them.
Light: Plants need adequate light in order to grow. They can be categorized into one of 3 groups depending on their light needs: Low light tolerant plants, medium light plants, or high light requiring plants. When selecting plants, make certain the one you purchase will do well in your location. To assist you in this process, Molbak’s color codes their indoor plant price tags for each of these light groups: a green tag indicates a low light tolerant plant, a white tag is for medium light plants, and yellow indicates high light.
Low Light Tolerant Plants do well in northern exposures and in the interior of a room. A good rule of thumb to use in determining whether the light is sufficient for these plants is to see if you could read a book comfortably in that location without turning on a light. If not, then a plant would also need additional light in order to grow.
Medium Light Plants grow well in eastern exposures or close to western or southern exposures. Many low light plants will also thrive in medium light areas, but medium light plants grow poorly in low light areas.
High Light Requirement Plants are those plants which need up to 4 hours of direct sunlight. Unobstructed southern or western exposures are ideal for these plants. High light areas tend to be more stressful on plants than medium or low light areas.
Plant health depends on quality of light as well as quantity of light. Natural daylight can be mixed with fluorescent or incandescent light to increase the quantity of light available to the plants, but some daylight is necessary for light quality. If trying to maintain foliage plants under artificial light, the light source needs to be close to the plant and left on for 12 to 16 hours a day, 7 days a week.
Moisture: Generally the best watering practice is to water thoroughly until all the soil is evenly moist and some water runs out through the drain holes. Remove any water left in the saucer. Let the plant get moderately dry between waterings. (No plant, including cactus, can tolerate staying dry for any length of time.) When a plant gets too dry, it is critical that the entire soil mass gets moist again. To saturate dry soil, run a lot of water through the pot, or let the plant sit in water until it cannot soak up anymore and then discard the rest.
A simple test for moisture is to pinch some soil (from as deep in the pot as you can get) between your forefinger and thumb, then let go. If the soil sticks together and clings to your finger, there is enough moisture for the plant at that time. If the soil is gray in color and crumbles, it is time to water again.
The problem of overwatering is not in how much water is used, rather it is how often the plant is watered. Always water thoroughly and then let it get moderately dry (not bone dry) between waterings. Frequency of watering depends on day length, quality of light, and temperature of the room. Plans use less water during shorter days and cooler temperatures and therefore will not need as frequent watering.
Humidity and Temperature: Humidity and temperature are interrelated; plants can withstand higher temperatures if the humidity is also higher. Humidity is increased by room humidifiers, plant groupings, misting, or humidity trays. Humidity trays are the most effective after room humidifiers. A humidity tray is simply a deep, oversized saucer filled with pebbles. Place the plant on top of the pebbles and fill the saucer with water to a point below the bottom of the pot. The water will evaporate from the tray adding moisture to the air around the plant.
The lowest temperature most houseplants will tolerate living in is 50-55° F.
Fertilizer: Feed with a balanced houseplant fertilizer as directed on the label, from March through October. The frequency and strength depends on the fertilizer being used and the amount of light the plant received. Plants in lower light do not use as much fertilizer as plants in high light. Fertilize plants in high light according to package recommendations; in medium light, cut the rate in half. In low light, once or twice a year in spring or summer is enough.
When plants are not growing well, usually the last thing they need is fertilizer. It is important to determine why the plant is unhealthy before deciding to fertilize.
Pests: Check your plants regularly for insect pests. If you suspect an insect infestation have the insect identified so that you can properly control it. Washing leaves with soap and water can help prevent serious infestations. When a more direct control is needed, you must treat at least 3 times, allowing 7-10 days between treatments to gain control. Insecticides only kill the adult stage of insects so any eggs that hatch must be eliminated before they lay more eggs.
Frequency and coverage are the keys to success in spraying. Most insecticides are contact killers so you have to wet all leaf surfaces and stems with the spray. The soil should be moist when you spray to lessen the possibility of burning the foliage. Choice of chemicals is important, too. Systemic insecticides put in the soil do not work on very woody plants or on a plant that is not actively growing. Always read the label before using any product. Be sure the product is labeled for the pest you are trying to control.
Other Comments: Plant health management begins with proper plant selection. After plant selection, health management is a matter of providing a well balanced environment for your plants. When one environmental element becomes unbalanced, the plant becomes stressed which leads to poor plant health. Environmental elements that can become unbalanced are: Light, watering, temperature, humidity, container size, potting mix, fertilizer, insects, and disease. Several stress promoting elements of the environment may affect plants at the same time. The symptoms you see on the leaves are often a reflection of the health of the root system. Plants must maintain a root-shoot ratio. If a percentage of the roots are damaged, that percentage of foliage will either drop off or deteriorate.
The ability to recognize symptoms, determine the causes, identify the environmental stresses involved and correct the care practices are the secrets to good plant health management.