While we don’t intend this to be a comprehensive guide to growing success with Cattleya alliance orchids, here are a few tips we would like to pass along. We consider these to be among the most vital elements for producing orchid plants that grow and flower well.
Other factors not withstanding, the single most important element in our opinion is ADEQUATE LIGHT! With only a few exceptions, Cattleya alliance species and hybrids like bright to very bright conditions. Essentially, as bright as they can take and still have proper humidity, air movement and temperature will produce plants that bloom better, more often and with better substance and richer color than plants in less light. In particular bright light in winter is essential. In the tropical regions where these orchids grow, the sun does not sink to as low an angle as here in the temperate zones. In addition, many of the Cattleya alliance species grow in deciduous tropical forests, where, due to lower rainfall, trees lose their leaves in the winter months, exposing the plants to higher light. So for many orchids, this bright winter light is essential for truly impressive blooms the following season. We grow our plants under 2 layers of 15% Aluminet shade/heat protection, plus the additional diffusion that the twin wall polycarbonate covering of the greenhouse provides. This creates just enough scattering of the light to imitate the bright conditions of dappled sunlight that most Cattleya get in the wild. But we also roll up the shade cloth on November 1st and don’t roll it back down until between February 15th and March 1st, depending on how cloudy or sunny. You may be surprised to learn that we even grow our personal Phalaenopsis collection under bright ‘Cattleya’ light and the plants flourish and bloom more heavily than they ever did under the typical recommended conditions for this class of orchids!
But, it should be noted that preventing the full sun of March from reaching your plants is also vital. This happens to be the month in which Earth is closest to the Sun in its yearly orbit, so that extra energy added to a brilliant clear day can burn your plants quickly! So NEVER wait to provide extra protection when March arrives. When growing inside your home, this can be as simple as adding a sheer drape between your plants and the window, or moving them back a few inches. If the leaves are hot to the touch, they have lost their ability to regulate their internal heat and will burn.
Next in line to adequate light, we believe is ADEQUATE HUMIDITY combined with AIR MOVEMENT. A typical home is a virtual desert to most orchids. They live in environments where, even in dry seasons, the humidity is regularly 60% or more during the day and approaching the dewpoint at night. At the same time, stagnant, humid air is the breeding ground for numerous orchid ailments, so what you are looking for is good humidity with good air movement at all times. In the home, you can usually accomplish this with a ‘fine mist’ humidifier and small fan placed with it to move humid, buoyant air across your plants. Of course, more elaborate systems are available. Nice green, fresh root tips are a good sign that your plants are happy and getting adequate humidity. In our greenhouse, we use a combination of evaporative cooling pads, jet powered foggers, exhaust fans and horizontal air flow (HAF) fans to create this balance whatever the season.
One also needs to take culture tips that call for a ‘dry winter rest’ with a grain of salt. Its one thing for a plant to live in a climate that has little rainfall for a season, but still receives high humidity and NIGHTLY drenching with dew, and quite another to withhold all water from the same plant captive inside your house or greenhouse, where no such environmental conditions exist. You can’t underestimate how much water an orchid can absorb when dew is condensing on it continuously for several hours each night, even though not a drop of rain falls for weeks upon end. So, to imitate this in some way, you should either water lightly from time to time, or syringe, or mist your plants almost daily in bright weather during this ‘dry’ season. If the pseudobulbs are shriveling more than just a little, the plant is suffering from lack of moisture. With practice and experimentation, you can find a method that still delivers the needed moisture without overdoing it.
Still of great importance is PRUDENT WATERING of your plants. With very few exceptions, the members of the Cattleya Alliance are adapted to cycles of wet and dry. Growing as they do and airy tree limbs and rocks, they will be thoroughly soaked by tropical downpours, and then will dry fairly quickly in the sun, warmth and air movement once the rain has passed. Their roots are encased in a spongy layer designed to become saturated, and the wick the water up into the plant slowly where it is stored in thickened pseudobulbs and tough leathery leaves. These roots CANNOT tolerate being constantly moist and will rot and die over time if they do not dry out and get a bit of air movement around them. But too much water also fails to stimulate the plants to produce new roots, so that over watering is something of a "double whammy" that can lead to a quick decline that takes the plant beyond the point of recovery. So our advice is to water VERY thoroughly, then refrain from watering again until the plants have been dry for at least a day. If in doubt, it is better to wait yet another day. It is much easier to revive an slightly under watered plant than an over watered one that has lost its roots to rot.
Learn to recognize by sight or weight when potted plants are wet or dry. Don't treat every plant the same, but evaluate each one since large plants in large pots, especially with aging media, will dry more slowly. Despite having thousands of plants to care for in our greenhouse, they are all hand watered so that we can make those snap judgments about each one as to whether more water is needed or not. Frequency of watering is NOT UNIFORM, but dependent on conditions. We never water during strings of cloudy damp weather when the temperature is cool and the humidity very high, but may have to water every two days in very bright, dry weather, especially in spring and fall when the humidity can be quite low as well.
When the media is breaking down and a pot is beginning to stay wet too long, repot your plant at the earliest opportunity. This is ALWAYS when new roots are forming from the most recent growth, regardless of time of year.
Lastly, ADEQUATE NUTRITION makes the big difference. While orchids are not generally heavy feeders, they depend and a wide spectrum of trace elements in their environment to produce healthy plants. We collect rain water from our greenhouse roof and add the MSU (Michigan State University) fertilizer to it at ¼ strength. The formula was the result of much research and provides small amounts of 13 essential elements to our plants. We are giving our plants this diluted strength fertilizer with each watering. About once a month, we flush all the plants with plain water to avoid salt buildup in the pots, which can destroy roots. We are also experimenting with foliar sprays of additional iron and calcium with our mini-catts based on the success of other orchid colleagues. We are always learning, and you should be too. Suffice it to say that the days when plant nutrition was based solely on Nitrogen, Potassium and Phosphorus are long gone as we begin to understand that orchids, like humans, rely on a host of trace elements for good health! The ‘work’ of learning more about these needs pays high dividends for the orchid hobbyist.
DEALING WITH ORCHID PESTS
HOW YOU CAN GET RID OF SCALE AND MEALYBUGS FOR GOOD!
Anyone who has grown orchids for any length of time will undoubtedly know that the two most annoying, and heretofore difficult to eradicate pests, are scale and mealy bugs. Both of these insects survive by sucking the vital nutrients from their host plants, and thrive in the same conditions that orchids love. Most traditional insecticides are only somewhat effective at keeping their numbers down, but not putting an end to their reproduction altogether, as their larvae and eggs can often hide in roots, pots, and other difficult to reach places. In the past, we found a mixture of isopropyl alcohol and liquid soap to be just as effective as more toxic products like Malathion and Orthene. But no matter what method we used, it took great persistence and constant vigilance to keep these two pests under control, especially in some of the large, old specimen plants in our breeding stock and private collection. We have heard several hobby growers over the years lament how they had given up growing orchids in the Cattleya group entirely because of the difficulty in controlling scale and mealy bug.
FINALLY there are products available which can truly, totally eradicate these two pests in just a few applications, and your collection can stay free of them indefinitely unless you re-introduce them again by accident. This new class of product is NOT an insecticide, but instead an Insect Growth Regulator that interferes with the pest’s ability to mature into adults capable of reproducing. Since both of these products have systemic qualities (absorbed into the plants) and the life cycle of these two pests is relatively short, a few applications spaced 10 days to two weeks apart are normally all that are needed to totally eliminate these bad guys from your growing area for good! We used two products by Valent Professional Products, Distance and Safari to do the trick for us. And after more than one full year since the last application of either, we still have not found a single living scale or mealy bug in our entire greenhouse! Both these products are designed to target a small group of specific pests without harming other organisms that are considered beneficial, so our resident population of Carolina Anole lizards, Five Lined Skinks, Gray Tree Frogs, and American Toads are still thriving in our growing area, and providing biological control of other types of insects that find their way in.
The only negative side to the Insect Growth Regulators is that so far they are only available in commercial quantities that are rather pricey. The smallest size available of either of the two we used would be enough to treat many commercial growing areas for a very long time. However, we know of several orchid societies that have pooled their resources to buy these products and split them up into quantities practical and affordable for the average member, so this is an idea you might share with your club or a group of friends who also grow orchids or other plants that are plagued by any of the pests the IGR’s control.
The IGR’s do not totally control thrips or spider mites, which are pests of lesser magnitude that can sometimes bother orchids. Both of these are very tiny guys that can disfigure flowers and softer foliage. They thrive in dry, warm air, and are more of a problem for those growing their orchids inside their homes than in a designated, humidity controlled environment, especially where regular overhead watering is in use. Both can be controlled on a small scale with the typical alcohol and soap home remedy, sprayed on affected foliage. If their population explodes, there are propriety products that are effective. If you have a greenhouse, consider enclosing your air intake vents in a ‘cage’ made of insect screening that is fine enough to keep pests as small as thrips from entering in the first place. We did this several years ago and have never had any problems since. Several online greenhouse supply companies sell these products in panels of specific size and by the foot in specific widths. The ‘cage’ we built on the outside of our greenhouse over the intake vents was designed to be roughly twice the square footage of the vents themselves in order to account for the ‘drag’ created when the screens get wet from rain.
Snails and slugs can be a problem for orchids, especially in damp greenhouses or when growing or ‘summering’ your orchids out of doors. These mollusks especially enjoy lunching on tender new root tips, new growths, and sometimes even flower buds. There is nothing more frustrating that waiting for months to see your plants bloom only to have developing flowers become slug salad! Unfortunately, the chemicals that effectively kill snails and slugs are highly toxic to the environment and usually available only to commercial growers with special licenses to use them. We find that the palletized products that are sold in garden centers, and which do not contain toxic products, are relatively effective if used with vigilance, although they become moldy and unsightly for a while until they break down completely and are washed away. Careful planning and design of your growing area can serve to greatly reduce the chances that large population of these pesky creatures get established in the first place.
Instead of using gravel or poured concrete for the floor of your greenhouse, consider instead a layer of crushed granite or sand, overlaid with black landscape fabric. We used this method in our greenhouse and it not only provides quick drainage when the plants are watered, but a surface that is easily swept or vacuumed to keep it clean and free of debris. Keep plants up off the ground or floor on benches and provide as few places for snails and slugs to hide and breed as possible. Rather than watering frequently, water thoroughly, then allow your epiphytic orchids such as Cattleya, Encyclia and Dendrobium to dry out before watering again. This helps provide a less ‘friendly’ environment for snails and slugs.
When ‘summering’ your plants out of doors, keep them up off the ground and off wooden decks. Either buy or build some wire racks or hang your plants to make them less accessible to the snails and slugs that are likely to be lurking about. If you notice that new roots are being eaten on a specific plant, check it carefully, especially when the media is damp. Some types of snails can be very, very small. Crush any that you find and sprinkle a few snail pellets in the pot and in the area around it. If you follow these tips you should be able to avoid a problem that impacts the health of your plants.
We hope these tips have proven helpful to you and appreciate any feedback or questions you may have for us. You should find, like we have, that getting rid of the two major orchid headaches, scale and mealy bugs, has made it much easier and more enjoyable for us both as commercial growers and as fellow orchid lovers. ALWAYS follow all directions and safety precautions issued with any proprietary products you use to control pests!!!
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