'Other World' CHM/AOS.
|Some Basic Concepts for Growing Orchid Species|
by Jeffrey Parker (2002-06-01)
Congratulations! You have chosen as your avocation (or pastime) the most interesting and enjoyable field in all of botany! After all, orchids are by far the largest plant family, the most diverse, and the most written-about group of plants. Fortunately, orchids are among the most adaptable of plants. A testament to this is the fact that our nursery somehow manages to grow maybe 2000 different species, whose natural habitats range from sea level to over 10,000 ft in elevation! Our greenhouses are not closed-in, so we have no control over temperature at all. Some of our plants come from wet montane forests, while others come from hot dry lowlands. We do enjoy good growing conditions here in windward Maui. However, there have been many instances where customers of ours, with seemingly less-than-ideal growing conditions, have grown a particular species far better than us -- winning cultural awards from the American Orchid Society, etc.
Because every grower's conditions vary so greatly, it is impossible for me to tell you exactly how to grow orchid species. What we can do in this short article is to lay out some basic concepts to help you formulate or refine your own cultural techniques. The best source for specifics is still other local growers in your area. Join a local society to meet growers more experienced than yourself, who will generally be very nice about helping you. This article does not for the most part, discuss particular fertilizers, insecticides, or potting medias per se.
1. Orchid culture is about "a balancing of factors". The different factors are light, humidity, water, temperature, air movement, and feeding. When one of the factors is out of balance, another might be adjusted to compensate. For example, if you can't give your plants an ideal amount of light, you might then cut down on the watering and fertilizer. Conversely, if your plants are receiving high light, you might compensate by watering more often and feeding more. If your plants are getting root-rot, you could add more air movement and cut-down on how often you water.
One time, we had a large group of identical vandaceous mericlones that were growing well under extra shade. A fungal or bacterial problem emerged that was spreading like wild-fire. We could see that it would soon ruin the entire crop. It happened in the dead of "winter", when days are shorter, temperatures are cool, and sunlight is weak. Rather than go crazy spraying a bunch of toxic fungicides, we "balanced the factors" by simply removing the extra layer of shade-cloth, thereby increasing the sunlight. The infection immediately stopped dead in its tracks. You see, the particular disease organism thrives in a very specific niche of shade, humidity, and moisture. We merely changed the niche slightly. Regarding fungicides in general, I've always felt that it is far better to change the way you are growing the plants than to try to make up for wrong culture by spraying these potentially-dangerous chemicals. There are appropriate uses of fungicides also, but too often they are used solely because of some misplaced belief that they are a cure-all.
2. Orchids tell you what they want! Unfortunately, as the old adage goes, "orchids tell you what they want, but by the time you listen to what they are trying to tell you, they are dead". For example, if a plant would like to be in more shade, it will grow in the direction of nearby shade. If a species is being watered too often, its foliage may start to spot-up with fungal or bacterial infections. Or, its roots may start to look soft and brown (rot). Get in the habit of carefully pulling the plants out of their pots to inspect the roots.
3. Growing orchids in pots is an unnatural act. In nature, epiphytic orchids grow on trees with their roots fully exposed to the air. The roots can dry-off very quickly after a drenching rain. This explains how an orchid can receive hundreds of inches of rain per year in its native habitat and never get root-rot. A cattleya root-system may cover a hundred square feet of tree branch and trunk area or more! So, when you try to confine that big root system in a closed 5" pot, of course it can cause problems! Having said that, we do use pots in our nursery, because there remain several advantages to pot-culture. One just needs to be aware that you are beginning with an artificial situation and therefore increased vigilance is warranted.
4. You must repot or re-mount your orchids on a regular basis. Whether you grow your orchids in pots or mounted, the growing media will go sour! And surprisingly quickly, I might add. Yes, even plants mounted on expensive cork bark will quickly go downhill when the cork gets "old". Exceptions: Some growers report that hardwood mounts, with little or no sphagnum added, can last a very long time. Also, we have begun to grow some species hanging in empty plastic net pots. These would theoretically last indefinitely, as long as you water enough to keep plants from desiccating. Many orchidists will use a pad of wet sphagnum moss on their cork or hardwood mounts, to help the plant get established. Sphagnum moss works great initially. It is a tremendous resource for growers, but it can quickly go sour. Later you discover that all the roots within the sphagnum are dead. A good root system is the most important thing!
Contrary to popular belief, most of the time orchids do not mind being disturbed. Generally they get a boost from growing into fresh media. For example, Paphiopedilums like fresh media all the time. Some paph growers "refreshen" (repot) up to four times a year! Notwithstanding paphiopedilums, orchids generally prefer to be disturbed at the right time of the year, and it can be a different time for each species. So, how do you know when to repot? Simply observe the plant. The ideal time is when the plant is in active growth and new root-tips are just beginning to emerge. This way, the roots can grow into the new media immediately. Otherwise the plant might have to sit there for half-a-year without roots, and no way to take up water or nutrients (our Dearly Departed...). In our commercial nursery, we have so many thousands of plants that sometimes we just have to repot, regardless of root activity. However, if we already know a certain species can be "touchy", then we wait until new roots are emerging. If you do have to repot when a plant is inactive, give water sparingly and coax the new growth out with your careful observations and love. The famous and controversial book 'The Secret Life of Plants' (Tompkins, Bird, 1973) cites experiments in which the thoughts and beliefs of the person tending the plants were found to dramatically affect the rate of growth and health of the plants!
5. Don't be intimidated by species which have a winter resting period. Serious species people want to be able to grow all those fabulous genera like Mormodes, Catesetum, Lycaste, and even Laelias. In actuality, while not always critical, many orchids would prefer a drier winter treatment. In our nursery, we handle the species which like a "resting period" by setting aside a special area of the nursery where these genera are located. All we do is set the watering-schedule to a much less frequent interval. Even in the "growing-season" this part of the nursery is kept drier than other parts. For example, during the summer growing season if the regular nursery waters every third day, then the "dry" section waters only on every fifth day. In the winter, the "dry" section may only water every seventh or eighth day depending on what the weather outside is doing. Also, we don't worry about cutting-off the fertilizer. Everything in the nursery gets the same fertilizer treatment at each watering, but because we are cutting down the watering in the "resting" section, the fertilizer is automatically cut-down.
6. Take notes. Be sure and note when something you did worked well... or did not work well! If you are like me, you will not remember later what you did. The idea is to assemble a knowledge-base over years. Sometimes killing a valuable plant is worth it, if something momentous is learned.
7. Modestly begin collecting books. Some folks will spend hundreds or thousands of dollars on plants, and never think of buying a book. The value comes from being able to look-up later (when you need it) something about a new species, or about its habitat in the wild. For example, a citation on a particular species may say "Epiphyte low on tree trunks on river banks in very wet montane forests, in Colombia and Ecuador. Elev. 1400 meters". Then you will know at least that the plant likes intermediate temperatures, high humidity, being wet all the time, and appreciates the somewhat brighter light of the more-open river banks. I used many books to prepare the descriptions in this catalog.
Books are also useful for citing synonyms, this will help you save money by not ordering the same plant twice, or ordering a species which you already know you are not fond of. As a basic starter book, all serious enthusiasts should own 'The Illustrated Encyclopedia of Orchids' (Alec Pridgeon, 1992). At $39, this is the bargain of the century! It describes over 1100 species and includes sections on history, culture and pest problems.
8. Feed your orchids! Up until recently, there were old-timers who still insisted that orchids do not like fertilizer and could be harmed by feeding. This idea has now been universally rejected. Orchids, like most plants, do need copious nutrients. The idea should be to keep the plants growing so fast that they outgrow any diseases and pest attacks. In nature, there is a constant accumulation of decomposing leaf-litter, animal and bird droppings, mosses, and enzymes to sustain the plants.
This article is too short to discuss various fertilizers. I will instead give four helpful hints: First, for a species collection, obtain fertilizers that derive their nitrogen from nitrates and ammonia, not from urea! Urea is responsible for some of the unsightly leaf-tip burn on "soft-leaved" species. Second, always soak the plants really well with fresh water before foliar fertilizing. Thirdly, if you have a hard time being consistent with your foliar feeding, and your orchids are in pots, then a pellet time-release fertilizer in the pot will help a lot. And finally, as your interest grows, keep revisiting the feeding issue. There is no limit to how much you can refine your feeding regimen. For example, many advanced growers pay attention to the different minerals and micro-elements as well as the standard nitrogen-phosphorous-potash ratios. Seek advice from experienced growers in your area, or your local horticultural supply house.
9. Be on the look-out for bush snails. Some growers may not be aware that they have the problem, because bush snails are sometimes so tiny that you don't notice them. You will, however, notice that the delicate root-tips of your orchids always look nibbled-off. This is a losing scenario. If the root tips are always eaten, then they cannot grow into the medium, and your plants will go into a long slow decline. I'm singling-out this one pest problem because I think it is a widespread problem, the importance of which is underated by many growers, and which is easy to correct. We use a fine 7% metaldehyde granule, which we broadcast over the plants and into the pots. This must be done at two week intervals for awhile to stop the egg-hatching cycle. Try not to get the granules down into the center of new growths. Plants on hanging mounts or baskets are subject to bush snails also, so you need to throw the bait up on your mounts as well.
Go forth and grow!
Copyright 2001 All Rights Reserved.
MILTONIA clowesii 'ALTA'
'GREEN' x self.
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