Orchid Care / Culture Data
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Cymbidium orchids are hardy plants and are easy to grow. They like the same conditions as we do, temperatures in the 20' s, humidity of about 50% and shade in the summer. Most amateurs can grow orchids well but have difficulty in flowering them. This usually can be overcome by finding a position where the plant receives more light.
Cymbidiums will tolerate full sun throughout the year, but it is best to find a position where they will receive 50% shade in summer. Remember too much shade will cause a decrease in flowering. 50% shade cloth is the best to use otherwise a very open shaded tree. Don't crowd your orchid plants, an empty pot of equal size should fit between.
This will depend on the type of potting mix used, position of orchid and atmospheric conditions, temperature and humidity. In winter, once or twice a week is sufficient in the morning. In summer, water daily at night. The night time watering is to reduce temperature. The drop in temperature helps in the initiation of flower spikes. In heat wave conditions watering may have to be done twice a day. When watering thoroughly saturate the potting mix. Stop when water comes out of the bottom of the pot.
Everyone has their own thoughts. I don't do any liquid fertilizing but add slow release fertilizers to the potting mix. These include Nutricote and Magamp at a concentration of two tablespoons to a two gallon bucket of potting mix. If you want to liquid fertilize use half strength Aquasol fortnightly during the warmer months of the year.
Again there are hundreds of combinations. Weathered pine bark with the above slow release fertilizers gives excellent results. The pine bark pieces should be about 10 to 15mm in size. Never pot an orchid into sand, you will destroy its roots. The mix should be open. Water should run straight through the potting mix.
Pine bark breaks down and will retain the water in the pot. At this stage, usually every two years the orchid should be potted into new mix. Use plastic pots and don't over pot. Give the plant enough room for one to two years only.
When the plant gets large the plant may have to be divided. When dividing, make each piece have a minimum of three green bulbs. Best time is after flowering or in spring. Try not to exceed pots of 250mm in size, they become very heavy.
The old bulbs without leaves can be individually potted. This is done when repotting or dividing. These old bulbs usually will produce a new shoot, which can be grown up to a flowering plant.
ORCHIDS IN SPIKE
A flower spike can be supported using a bamboo stake once it reaches about 15cm high. Spikes appear at the base of new growths during February to April. The flower spike at this stage looks like a fat pencil. At this stage snail pellets should be put around the pot and on top of the potting mix. When the flower buds break through the protective sheath the plant should be moved to a position so the buds are protected from strong winds and frost. Don't place the orchid in a dark area as the buds won't open. A verandah or patio is ideal.
ORCHIDS IN FLOWER
When the first flowers open then the plant can be taken inside. Water the plant once a week and cut the flower spike off no longer than four weeks after the first flower opens. Put the flower spike in a vase and cut 1 to 2cm off the bottom of the stem once a week at the same time changing the water.
The main problem is fungal infection. If good air movement occurs in the growing area then fungal infections will not occur. Any fungicide can be used, e.g. Benlate, Fongarid or Previcur. Then next biggest problem is red spider. Don't apply insecticide or fungicide sprays to flower buds, they can deform them. Use a powder.
Cattleyas grow quite easily in our climate and are very rewarding with their spectacular brightly coloured blooms. They can be grown under a range of conditions. The following notes are a guide how to grow cattleyas.
Cattleyas require less light than cymbidiums, about 70% to 80% shade. They will grow under brighter conditions if the plant is acclimatised to it slowly. They grow best in a glasshouse with 70% to 80% shading but will still perform well under fibreglass sheeting.
Cattleyas can be grown successfully cold, without any form of heating and will still flower well. If given heat during the winter (a minimum temp of about 12°C) they will continue to grow without a rest and small plants will mature more quickly. Flowering size plants may flower twice a year with heat. Cattleyas need to be protected from frosts and therefore in winter should be grown under fibreglass, glass or other protective material. The protective covering will also prevent over watering from winter rains. All orchids prefer air movement, the more the better.
In nature, cattleyas grow on tree limbs and forks of limbs so they require a very open mix. Make sure the potting mix used is very open. The roots act like a sponge and will hold water. If the potting medium is constantly wet, the roots of the Cattleya will rot and the plant may be lost. We use weathered pine b~rk. The pine bark size is larger than that used for cymbidiums, approximately 1 0-20mm chunks. I do not add lime to the pine bark but let nature weather it. It takes about 6 months to weather the bark. During this time it is kept constantly moist. If not weathered, toxic substances will be released, nitrogen will be robbed from the plant to break the bark down and the plant will dry out excessively due to the new bark not holding the moisture.
Rate of watering depends on numerous factors, climate, potting medium, size of the plant and where they are grown. If the potting mix used is of a very open nature then it is hard to over water your orchid. We grow cattleyas under fibreglass and in a glasshouse. We try to provide as much air movement as possible so they dry out very quickly after watering. In summer we water once a day in the morning using over-head sprinklers. In autumn and spring about every second day and in mid-winter about every third day depending on the weather. In winter, if very wet and humidity is high the watering can be delayed for 4 to 7 days. We do not dry out our plants to the extreme that the bulbs shrink.
Cattleyas obtain nutrients in nature from bird droppings and broken down leaf matter that falls around it. We do not believe in the use of a lot of fertilizers. We add slow release fertilizer to our potting medium at the rate of one tablespoon to a 200mm pot (8" pot). The slow release fertilizers we use are Nutricote (3-4 month release) and Magamp. The slow release fertilizers are mixed into the pine before potting.
Large Cattleya plants will still grow and flower well when the new growth has reached the edge of the pot and its roots are outside. For best appearance these plants should be either repotted or divided. It is best to repot or divide in spring. Cattleyas should be repotted into new mix at least every two to three years otherwise the root system will start to deteriorate. Small plants will require potting at a more frequent interval until they reach a 150mm size pot. They are best grown in a plastic squat pot with extra drainage holes cut in the bottom.
I like to grow my cattleyas into large specimen size plants. When dividing cattleyas, three or more green growths should be in a division. Cut through the rhizome with a sterilized knife where the plant is to be divided and place a small object (such as a match) to keep the cut apart. After a few months the old division or backcut will develop a new growth. At this stage repot each piece.
PESTS AND DISEASES
The biggest problem is fungi (black rot). The best preventative is good air movement or ventilation. In autumn and spring it is best to apply a fungicide such as Fongarid. If a leaf develops black rot, cut the diseased area out and soak the plant in Fongarid for 15 minutes. Other pests such as scale, mealy bug, thrips must also be watched out for.
Don't open the sheaths if possible. Let the buds break through on their own. If the sheath goes yellow then tear a small hole in the base so excess water drains out. If torn open at the top, water will collect in the sheath and rot the buds. Once the buds are exposed watch for pests and put snail pellets around. There are two main flowering seasons, spring and autumn. With good culture a plant may flower twice a year. Flowers normally last one to two months and can be strongly perfumed.
Paphiopedilums are more commonly called ‘paphs’ or slippers’. In nature they grow in decaying organic matter, principally in the south eastern Asian countries. Some plants have a very attractive mottled leaf pattern. Flowers can last a long time, four to six weeks even as a cut flower. Their flowers exhibit a large variation in shape and colour. They are easy to grow and are very rewarding. The following information is a guide to help you grow these plants successfully.
Paphs are low light orchids and will burn severely if given direct sun (80% or more shade is required to prevent burning), this shade should be applied all year. They can be grown successfully indoors, near a shaded east or west window. The ideal amount of light is achieved when no shadow is cast when a hand is held above the plant. Too much shade causes soft growth and reduced flowering. The plant will also be more susceptible to disease.
In nature paphs can be found in regions ranging from sea level to higher altitudes in the mountains. This means some plants will grow “cold” while others will require heat in winter to grow best. Mottled leaf varieties will grow slowly during winter when grown cold compared to plain leaf types. For best growth a minimum of 12° should be aimed for. Cooler temperatures are not detrimental, providing the plants are kept a little drier. Maximum temperatures up to about 30° will not cause stress to the plant. Higher temperatures can be reduced by increasing shade and ventilation. Plants grown in the house are happy with temperatures humans prefer.
All orchids like fresh air. Good air circulation reduces attack from fungus and bacteria and ensures the foliage is dry by nightfall.
Paphs should be slightly moist at all times. This does not mean soaking wet or leaving pots sitting in a saucer of water. Enough water should be supplied so it runs out of the bottom of the pot. We water our plants three times a week in the very hot summer, reducing to every third or forth day during the winter. Underwatering can lead to a salt build up with the consequence of a loss of plant roots.
Ideal humidity is 50% to 70%. Since plants have no storage organs (bulbs), humidity must be closely monitored. Dampening down around the plant is better than misting since it reduces the salt build up on leaves and the chance of leaf rot due to water accumulating in the leaf axils.
Paphs are extremely light feeders. A liquid fertilizer can be used, half strength Aquasol or similar every fortnight during the warmer months. Never feed a dry plant.
We are using a pinebark called “Aus Gro”. Depending on the plant size we use either grade 1 or 2, (small size). Many different types of mixes can be used providing they allow free drainage plus possess water retentive properties. Small plants should be repotted every year, larger plants every second year.
PESTS AND DISEASES
The only troublesome pest that attacks paphs is the mealy bug. Malathion will eradicate it. Bacterial and fungal rots occur if culture is poor. Increase ventilation and reduce watering. Remove the diseased parts if possible and spray with a fungicide/bactericide or sprinkle the diseased part of the plant with cinnamon powder.
These notes are only a guide as growing conditions vary from one place to another. For good culture, observation of your plants is essential. We wish you success and enjoy the rewarding outcome!