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African Violets are the favorite blooming houseplant and the easiest to grow. With good bright light and regular feedings, they will be blooming joyfully all year long. Just follow these easy tips and tricks to properly care for your African Violets.
LIGHT
Insufficient light is one of the major reasons Violets do not bloom well. Violets must have 10 to 14 (16 is max) hours of bright light per day (no direct sun). Variegated varieties usually need more light than the plants with solid green leaves because there is less chlorophyll which is used to turn light into food for the plant. The special yellow blooming violet varieties need less light than all the other violets require. You can enhance the light for certain violets by sitting them on mirror tiles as large or larger than the violet. This reflects the available light back to the violet. If adequate natural light is not available or desired, twin tube fluorescent lights are ideal. Place the tubes eight to ten inches above the foliage for mature standard plants, and six to eight inches for miniatures, leaves, and seedlings. Because violets process nutrients during the "resting phase" (i.e. darkness) they should also have 8 hours of darkness per day.
TEMPERATURE
70° - 75° Fahrenheit is usually ideal, although 60° - 85° Fahrenheit is tolerated for short periods of time.
HUMIDITY
40% - 50% relative humidity is usually ideal. The humidity near your plants can be raised by supporting the plants over water. Wick watering is ideal for this because the plant sits on top of a reservoir of water.
POTS
Use "clean" plastic or ceramic pots. Terracotta pots tend to collect salts, harmful chemicals, and pests. We advice against using them. Don't use a pot which is too large. Never move a plant to a larger pot until the roots fill the present pot. Violets tend to bloom most when they are slightly root bound.
FERTILIZER
Either lack of fertilizer or too infrequent feeding is one of the reasons for lack of blossoms. Most growers use a "soil-less" potting mix with little nutrient content; this requires using a dilute fertilizer solution each time the plant is watered.
Peters 12-36-14 is our recommendation. Mix 1/4 teaspoon per gallon of water and use this mixture each time you water. Use "Natures Miracle" sprinkled over the top of the soil every 10 weeks. This will increase the amount of blooming by 4 times. (This is NOT NOT NOT the same product sold for pet odor and stain removal!)
WATER
Never use water that has been through a softener. Using distilled water all the time is not good either because it deprives the violet of trace minerals which would ordinarily be present in the water. Chlorine in the water might cause problems for the violet. Let the water stand overnight in an open container to let the chlorine evaporate out of the water. Bottled "spring water" is a good substitute if your tap water is not good. Use water which is room temperature (neither cold or warm.) Keep the violet "just moist", not wet. Never allow the plant to become completely dry. "Wick" watering is also a good technique. Place a nylon wick on the bottom of the pot with the loose end extending out of the pot about 4 inches. Hang the loose end of the wick in a container of fertilizer/water mixture (see above). Never let the pot touch the water - only the wick should touch the water. This wick will keep the violet watered for 2-4 weeks depending on the size of the reservoir.
HOLISTIC HOUSEPLANT CARE
There is really no such thing as a houseplant. People take plants out of their native habitat to grow them in their homes. These native habitats range from the warm tropics to cool mountain tops and from dry deserts to ponds. The indoor gardener should try to duplicate the plant's natural environment.
Plants with different cultural requirements are often potted together as gifts. These should be repotted separately to meet each plant's individual cultural requirements.
The holistic approach to houseplant care integrates all of the cultural factors affecting a plant's health. These factors include soil, air, light, moisture in soil, humidity, fertility, pests, temperature, ventilation, plant size, the container and rate of growth. The following diagram illustrates the holistic system of houseplant health.
WATER
Watering is the number one houseplant killer. The well-meaning owner often waters too often. People place houseplants on a watering schedule with no regard for the plant's use of water. Due to varying cultural factors and changes in seasons, watering should be done on an as-needed basis.
Because houseplants come from a variety of natural habitats, it is important for the owner to know how moist or dry the soil should be. With so many houseplants being tropical or subtropical plants, general watering recommendations can be made. These recommendations assume the potting soil is well-drained and appropriate for the plant.
Apply water when the top 1 to 2 inches of soil are dry. Measure this by pushing the index finger about 1 to 2 inches down into the soil. Soil moisture cannot be determined by sight, except when a plant is wilted. Plants should never be
stressed to the point of wilting. However, some houseplants
should be kept nearly dry while others must be constantly moist. There are two methods of watering houseplants. The most common method is to apply water to the surface of the soil. Apply water so it runs out of the bottom of the pot. Allowing water to run out of the bottom ensures that roots in the bottom 2/3 of the pot receive moisture. If the soil is excessively dry, or the plant is pot-bound, water may flow through the pot without wetting the soil. In these two cases a second method of watering should be used.
The second watering method involves setting the container in water until moisture can be seen on the soil surface. This method, called bottom watering, periodically allows the root system to become completely saturated.
Never allow the pot to sit in the excess water that has drained into the saucer. Discard the excess water that collects in the saucer. Otherwise, the soil will become saturated, forcing air out of pore spaces. Without oxygen the roots cannot respire and they will die. The air spaces in soil are as important to plants as water.
The white powder that builds up on the pot and soil is SOLUBLE SALT. Accumulation of these mineral salts is common in houseplants because the container retains excess fertilizer and the naturally occurring salts in tap water. Signs of plant problems that may be caused by excess soluble salts include reduced growth, brown leaf tips, dropping of lower leaves, smaller-than-normal new growth, dead root tips and wilting. When salts concentrate in the soil, water is drawn out of the roots causing dehydration. Excessive salt buildup will eventually cause the roots to die.
Leaching will remove excess salts. Remove white powder residues from the soil surface and the pot. Pour a volume of water equal to three times the size of the pot through the soil. Discard the water that passes through the pot. Alternatively, take the plant out of the pot, clean the pot, remove all soil from the plant's roots and repot with fresh soil. If soluble salts are a reoccurring problem, reduce the amount of fertilizer applied and consider using distilled water.
The following are general suggestions for watering houseplants:
• Know how moist the soil should be for each species.
• Check soil moisture level and apply water based on the plant's moisture requirements.
• Use room-temperature water. This maintains a more stable root environment. Allow tap water to sit for an hour in an open container for chlorine to escape.
• Avoid using water that has passed through water softening systems, unless it goes through a deionizer to reduce salt content.
• Avoid wetting the crown of the plant.
LIGHT
Light is essential for plants to photosynthesize. Survival of a plant in a particular location depends on the available light in that location. Houseplant culture requires a close look at the light available in a particular room. Ask these questions when considering light level:
- Which direction do windows face? South-facing windows receive the most intense light. Heat buildup may be dramatic and it can burn foliage. Houseplants that require direct sunlight should be set back 6 inches from the windowpane.
East- and west-facing windows have 2/3 of the light available through south-facing windows.
North-facing windows receive 1/5 of the light that south windows do. North windows are also the coolest.
• What things outside and around the window affect light? Trees and shrubs, buildings, awnings, curtains and dirt on the window affect the quantity and quality of light that houseplants receive.
• How far away from windows will plants be placed? Once out of the direct rays of sun, the level of light available to a plant drops drastically.
• Are nearby surfaces bright or dark? Light-colored walls reflect light onto plants. Dark walls absorb the light.
• What are the light requirements of the particular plant?
Houseplants may be classified by their light requirements. The three levels of light requirements are: low, medium and high.
Follow this test to determine level of light in a particular location. Hold your hand 12 inches above a sheet of paper. If there is a definite shadow, the level is classified as high light. If there is a fuzzy shadow, the light level is medium. And if there is no shadow, light level is low.
Some plants are short-day or long-day plants. Special care is required to produce blooms. Poinsettia, kalanchoe and Christmas cactus flower only when day-length is less than 12 hours. However, most flowering houseplants are not sensitive to day-length.
Houseplants with VARIEGATED leaves need more light than plants with plain green leaves. Variegated leaves have pale or colored sections that contain no chlorophyll. Chlorophyll is necessary for photosynthesis. Therefore, the rest of the leaf must be exposed to more light to compensate for the nongreen areas that cannot contribute to this life-sustaining process.
Houseplants will grow toward the source of light. Phototropism describes the plant's tendency to grow toward light. If plants are not rotated regularly, they will become disfigured. Turn plants on an as-needed basis to maintain fullness on all sides.
Too much light can cause leaves to curl at the tips, develop yellow or brown splotches, wilt or fade to a lighter color. Too little light can cause straggly growth, smaller new leaves, bud drop and reduced flowering. Internodes will be very long and variegated plants may revert to solid green if there is not enough light..
Remember, the light that comes in windows changes with the seasons. You may need to move some plants away from the strong sunlight that pours in through south-facing windows in the summer. However, in the fall and winter this south window may be ideal. Learn to recognize the signs of light stress and know the requirements of each plant.
If the light available is less than ideal, artificial light should be considered. Incandescent bulbs produce too much heat to be used with plants. Special grow lights are the best choice, especially for blooming houseplants. Fluorescent bulbs, one warm-white and one cool-white bulb are adequate for most foliage plants.
If artificial light is the main or only source of light for plants, the lamps should be lit 12 to 14 hours per day and be 6 to 12 inches from plants. Blooming plants will require up to 16 hours and should be no more than 4-6 inches away from lights. It is important that some indoor plants have a regular light/dark schedule.
TEMPERATURE
Home temperatures fall into three categories: cool (55 to 65 degrees F), average (65-70 degrees F), and warm (70 to 85 degrees F). Most foliage houseplants grow best between 70 to 80 degrees F during the daytime, and 60 to 68 degrees F at night. Most flowering houseplants grow well with the same daytime temperatures, but at night a temperature of 55 to 60 degrees F is better.
Temperature extremes should be avoided. Extremes may cause no growth or spindly growth, foliage damage or loss, and even plant death. A good rule of thumb is to have night temperatures 10 to 15 degrees lower than day temperatures.
During extreme outdoor weather, check the temperature near windows where you have plants. Keep plants away from heat registers, radiators, fireplaces or where the air conditioner causes drafts. Flowering plants are very sensitive to both warm and cool drafts.
HUMIDITY
Humidity is the amount of water vapour present in the air. Some plants require high humidity to survive. For others, extra humidity is ideal, but they will survive at normal home humidity levels. A third group should have low humidity.
For plants that require high humidity, the level in their vicinity must be raised. Most indoor humidity levels are not adequate for plants that require high humidity. There are a variety of ways to raise humidity: cluster plants together, humidify the air or place plants on a tray of moist pebbles. Misting plants is not effective for raising humidity.
FERTILISATION
The need to fertilise houseplants varies with rate of growth, age of the plant, desire for growth, and growing season. Frequency of feeding can vary from every two weeks to every several months during the growing season. A general rule for application frequency is fertilising at half the recommended strength, every 2 weeks from March to September. Do not fertilise most plants during winter months. Winter's reduced light and temperature result in little or no growth. Most houseplants are dormant during winter.
Houseplant fertilisers come in several forms: granular, crystalline, liquid, tablet and spikes. Most houseplant fertilisers are fairly concentrated. Never exceed the recommended application amount. Oftentimes, applications should be even more dilute than recommended. Label recommendations are based on the ideal conditions in greenhouses.
Spikes have the disadvantage of creating a high concentration of nutrients in the soil around them. This burns nearby plant roots. Liquid and crystalline forms of fertiliser are mixed with water and applied to the soil.
When applying fertilisers solutions to the soil surface, make sure that some of the solution runs out the bottom of the pot.
This ensures distribution of nutrients throughout the soil. Do not allow the pot to sit in this runoff.
When considering fertiliser applications, it is important to be aware of the growth rate of houseplants. Slow-growing plants need less fertiliser; faster growing plants will need more. Flowering plants usually require both more light and more nutrients. Type of POTTING MEDIUM influences when to fertilise. Newly repotted plants in soil-based mixture.
DISEASES
Houseplants grown under correct cultural conditions have very few disease problems. Poor growing conditions stress and weaken plants. Consider all factors affecting a plant's environment when looking for the source of a disease. A symptom may have more than one possible cause, and many problems result in the same or similar symptoms.
Diseases are most often a result of overwatering, poor soil conditions, too much or too little humidity and lack of air movement. General actions to take include isolating or quarantining diseased plants, removal of diseased tissues and possibly chemical treatment.
Root, crown and stem rots occur when the soil is kept too wet or the plant is damaged by cold temperature. In these cases, remove diseased tissue or take a cutting of healthy tissue to start a new plant.
Leaf spots can be caused by fungi, bacteria or growing conditions. Water drops remaining on leaves or high humidity are necessary for infection. Whatever the cause, the affected leaves should be removed and the probable cause corrected.
INSECTS AND MITES
Insects and mites may be a problem even under the best growing conditions. They come into the home on new plants or with plants which are put outside for the summer. Insects may come in on clothing or when the door is open.
Scale insects are among the most difficult to control. These insects are mobile when young, but then settle and secrete a protective covering that can't be penetrated by insecticides. The best control is a systemic insecticide.
Soft-bodied insects like aphids, mealybugs and whiteflies are easily controlled with insecticidal soaps and pesticides like malathion. Insecticidal soaps are relatively effective for mites. These tiny spiders feed on the underside of leaves. Miticides also effectively control this pest. Soil with a high organic content may result in infestations of fungus gnats and springtails. These insects feed primarily on decaying organic matter, but occasionally damage healthy plant tissue. Avoid soil mixes with a high organic content, remove fallen leaves from the soil surface and drench the soil with an appropriate pesticide.
POISONOUS HOUSEPLANTS
A few common houseplants are poisonous. All or portions of these plants may cause mild-to-fatal reactions if eaten by children, adults or pets. The American Medical Association has edited a book on poisonous plants which should be used as a reference. Anthurium sp. (flamingo flower), Diefenbachia sp. (dumbcane) and Nerium oleander (oleander, rose bay) are poisonous. The seeds of Ricinus communis (caster bean) and the bulbs of Hyacinthus orientalis (hyacinth) are also poisonous. The local poison control center should be consulted for treatment of poisoning caused by these plants.
POTTED PLANTS
Potted plants purchased for enjoyment during the holidays, for seasonal color, or given as gifts can be enjoyed with a minimum of care. However, too little light, excessive heat or cold, low humidity, and improper watering can significantly reduce the flowering period. Each plant type has it's own growing requirements.
Often homeowners attempt to grow flowering potted plants after they finish flowering. While this is possible for many plants, other plants should be enjoyed while they are in flower and then thrown away.
Amaryllis - bulbs will normally flower within six to eight weeks of planting. Place in bright light; direct sunlight can shorten the life of the flowers. The soil should be kept constantly moist; excessive drying will reduce flower life and cause the flower stalk to bend.
After the flower fades, cut the stem off just below the faded flower. For maximum bulb development, keep plants actively growing after they finish blooming. They prefer bright light to full sun, with a night temperature above 60°F. As soon as danger of frost has passed, set the plants in the garden in a semi-shaded location. In the fall, you can leave the bulbs in the ground or bring the plants back indoors to bloom again. Stop watering to allow old growth to die back, and store them in a cool, dark place to rest. They will be ready to force again about November 1. Place them into a warm, well lighted room and water moderately to begin new growth.
Azalea - Keep the plant in a well lighted location, but avoid direct sun while in flower. A night temperature between 55°F and 60°F will prolong flowering. Keep the soil uniformly moist; do not use softened water. Greenhouse azaleas are not hardy outside and should be discarded after flowering.
Calceolaria and cineraria - thrive in cool temperatures. Locate the plant in a cool room where temperatures are near 50°F to 55°F at night. Provide bright light but not direct sunlight. Excessive heat or dry soil can cause rapid decline. Keep the plant well watered with slight drying between waterings. After flowering is completed, the annual plants will gradually decline and can not be reflowered.
Christmas pepper - The fruit will be at peak color for one to two months. They will be brighter and last longer if you provide high light, mild temperatures (60°F to 75°F), and keep the soil moist. Fertilize weekly with a soluble fertilizer. The plant can be set outdoors after the danger of frost has past.
Chrysanthemum - Buy chrysanthemums when flower buds first show full color. Diffuse, bright light (but not direct sun light) and 60°F to 70°F temperatures will prolong peak bloom. Water often enough to prevent the leaves from wilting. Two types of mums are sold at retail outlets: pot mums (killed by frost) and garden mums. Garden mums are generally available in the fall as flowering pot plants. They can be planted outdoors and are hardy through the winter. Garden mums are perennials and will flower each year. Pot mums are greenhouse cultivars; they provide three to four weeks of enjoyment and should be discarded after flowering, as they are difficult to reflower.
Cyclamens - require bright light and a night temperature between 50°F and 55°F. Day time temperatures are less critical but should not exceed 70°F. Cyclamen is a heavy user of water and must be watered whenever the soil surface is dry. Flower buds will fail to develop if the night temperature is too high or if light is poor.
After flowering, gradually withhold water until the foliage dies back. This begins a rest period. Do not water for six to eight weeks. By mid-summer, begin watering gradually. As new leaves develop, move the plant to a sunny location and resume normal watering and fertilization.
Easter lilies - are grown specifically to flower for the Easter season. Choose strong-stemmed plants with evenly distributed foliage and four or more flower buds. Cool temperatures (55°F to 60°F) prolongs flowering. Keep the plants moist but avoid over watering. Keep the plant in a bright location but avoid full sun and drafts. Remove yellow stamens before the pollen sheds to make the flowers last longer and to keep pollen from staining clothing and furniture. Cut off faded flowers as they collapse. Easter lilies can be transplanted outdoors in most areas in North Carolina and will often rebloom the following June. It's difficult to reflower bulbs kept in pots.
Spring-flowering bulbs - To get the most color and greatest longevity from your spring flowering bulbs, buy plants when the flower buds first show color. Keep plants cool (60°F) to slow down flower development and to prolong the flower's life. They will tolerate temperatures down to 40°F. Keep plants well watered as water stress can cut the flowering time in half. Do not place them in a sunny location. It is not necessary to fertilize since the plant's useful life is two to four weeks. Most forced spring-flowering bulbs should be discarded after flowering.
Gardenias - The night temperature should be near 60°F and 70°F to 75°F during the day. Maintain high humidity around the plant and keep the soil uniformly moist. High temperature and low light intensity will result in flower bud drop. Some gardenia cultivars are hardy outdoors -- most florist gardenias are not hardy. Gardenias decline rapidly after flowering and should be discarded.
Geraniums - Potted geraniums are typically available March through June. Many new types are available, including vining and hanging basket cultivars. Bright light is essential to keep geraniums flowering. Geraniums respond favorably to having the soil dry out between waterings. Keep them in pots or transplant into the landscape once the danger of frost has passed. They are not winter hardy and must be brought indoors before frost if you wish to over winter them.
Gloxinias - need bright, indirect light; high humidity; and warm night temperatures (65°F to 70°F). Gloxinias need more light than African violets; place them in a bright window just beyond the reach of direct sun light. Keep the soil uniformly moist. Poor light, low humidity, and/or excessive soil drying can lead to the collapse of young flower buds.
Gloxinias need to rest before reflowering. When the leaves start to die back, gradually reduce watering until the leaves yellow and die. Place the pot in a cool, dark location and stop watering. Allow the tuberous stem to rest for a minimum of eight to ten weeks in dry soil. To stimulate reflower (although it's hard to do), resume watering when new growth appears and move the pot to a bright location.
Holiday cacti - prefer a relatively cool night temperature between 55°F and 60°F. Night temperature above 70°F inhibit flowering and cause bud drop. Place the plants in a well lighted location. Poor lighting leads to bud drop and poor growth after flowering. Water thoroughly, but allow to become moderately dry between waterings.
Holiday cacti bloom best when somewhat pot-bound. Repotting is necessary only about once every three years. Full sunlight is beneficial in mid-winter, but bright sunlight during summer months can result in pale to yellowish foliage. Holiday cacti require less water from October to March than when new growth is active (April to September).
Cacti will develop flower buds in the fall if the night temperature drops to 55°F. Where cool nights are not possible, cacti can be stimulated to flower by providing short days (11 hours or less of light each day) from mid-September to mid-October. This involves covering the plant with a light-tight box daily or moving to a dark location each night. Reduce watering and withhold fertilizer during flower bud development and flowering stages.
Hydrangeas - are generally recognized as outdoor flowering shrubs, but are also available as 6- and 8-inch pot plants in the spring. Flowers can last four to eight weeks if plants are bought as color first develops, watered adequately, exposed to mild temperatures (50°F to 60°F at night), and exposed to bright (but not direct) light. After the flowers fade, remove the flower heads and transplant into the landscape.
Kalanchoes - are available year-round in many colors. Flowers will last three to six weeks if plants are provided mild temperatures (60°F to 65°F at night) and medium light. Allow the soil to dry slightly between waterings; plants are easily damaged by over watering.
After flowering, cut off any tall growth and old flower stems. Keep the plants in a sunny location and move the plants outdoor after the danger of frost has passed. The best site is a bright, lightly shaded location. Kalanchoes will re-bloom if grown under artificial short days (long nights) for six to eight weeks. They can be grown successfully if kept in sunny windows or placed outdoors in late spring; they are not winter hardy.
Poinsettia - The colorful bracts of poinsettias may stay bright for months if cared for properly. If the plants are exposed to cold temperatures during transport home or placed near a draft the life of the "flowers" will be significantly shortened. Bright, indirect light (but not direct light) and frequent watering are essential. Do not allow the plant to wilt. Punch holes in the bottom of the decorative foil to provide drainage; poinsettias do not tolerate poor drainage. Temperatures between 65°F and 70°F are ideal.
Plants can be reflowered, although the procedure is somewhat demanding. Keep the plant indoors until the danger of frost has passed then move it outdoors. Remove the bracts when they wither and discolor. Keep the plant in high indirect light (morning sun/afternoon shade). Water and fertilize on a regular basis. Shape the plant as desired by pruning or pinching to encourage branching. Do not pinch after mid-August.
Bring the plant back indoors when night temperatures start to fall below 60°F. Continue to fertilize and water. Starting October 1, give the plant 14 hours of uninterrupted darkness daily until bract color is well developed (mid-November). This can be done by placing the plant in a closet or covering it with a cardboard box at night. Any light during the dark period will delay or inhibit flowering. Night temperatures should be between 60°F and 62°F. During the remaining 10 hours each day, provide maximum light with temperatures between 70°F and 75°F.
Orchids - are easily cared for if kept away from intense light and cold. They do very well under fluorescent lights or near a south facing window. Most orchids bloom only once a year, but the blooms can last as long as two months. Fertilize only when new leaves appear. Water often but allow the bark medium to dry out thoroughly between waterings. Orchids can be grown outdoors under the shade of trees after the danger of frost has passed.
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