There are two main reasons to re-pot your orchids, and they often, but not always, occur at the same time. First, an orchid needs to be re-potted if it gets too big for its pot. Orchids can have an extensive root system inside the pot and the potting mix, but they also typically have roots that extend out of the mix into the air, and this normal behavior is not usually a clue for re-potting. But when the pseudobulbs hang over the pot side or new roots can’t find their way into the pot at all, then that orchid needs re-potting.
The second reason to re-pot is because the mix has decomposed. If they’re made from natural materials, most potting mixes deteriorate with time, breaking down into a fine, tightly packed mix that closes out air. With no air, roots die, and the orchid is doomed unless it is released from that compacted environment.
To tell if an orchid needs to be re-potted, you should brush away the top of the potting mix and look at the materials underneath for signs of decomposition. Generally, if you can sink your finger in easily to the second joint, the orchid needs re-potting. Signs of decomposed roots -blackening and mushiness or graying and brittleness – are more potent evidence.
Different potting media in different conditions deteriorate at different rates. A mix of medium-size bark pieces will last about two years, while finer pieces may break down in half that time. Tree fern may last two to three years; rock doesn’t deteriorate at all. Using a mix that combines both decomposing and non-decomposing materials helps lengthen the time between re-potting.
Timing – The Most Crucial Part of Good Re-Potting
Re-potting gets its reputation for being difficult because people classically re-pot at the wrong times, and orchids are quick to show their resentment of bad timing. Timing is the most crucial part of good re-potting. Orchids go through cycles of growth. New pseudobulbs, leaves, and roots appear and elongate. After the leading growth or leaf is mature, there is generally a rest period. Afterward, flower spikes and sheaths typically begin, followed by buds and flowers. Most orchids initiate new growth in late winter and spring.
Each time an orchid is re-potted, its growth is disturbed. Orchids are more forgiving of other potting mistakes if they are at least re-potted at the correct time. In general, the best time to re-pot an orchid is when new growths and new roots are just beginning to form before those new roots reach even 1/2 inch long. For most plants, this occurs right after flowering. This means that nearly all re-potting should take place between February and June.
If the plant is left too long after the growth cycle begins before re-potting, it must struggle to re-establish itself. If the roots get broken or damaged by re-potting, they don’t make the branches necessary for a healthy and extensive root system. Energy expended to make replacement root tips is energy taken from flowering. But if plants are re-potted at proper times, orchids do flower on schedule the next year.
Handling new roots when they are tiny means minimum plant setback. New roots are exceedingly brittle, and there’s less chance of breakage if the roots are less than 1 inch long. Re-potting at this time gives new roots the longest time to grow before the next re-potting disturbance, and they’ll be growing into fresh mix. The plant will stay healthier if its roots are well established before it enters the rest period when no active plant growth is going on.
What To Do If Time Is Bad, But Re-Potting Is A Must?
Sometimes an orchid desperately needs reporting because the mix is so deteriorated or the plant is badly overgrown. Waiting until the proper cycle to re-pot may mean that the resulting root damage could hurt the plant more than re-potting could. Be as gentle as possible with plants potted out of time, watching them carefully afterward. If you find that the roots are rotten, clean the roots and pot the plant into a very small pot, and wait until the regular re-potting time to re-pot as usual. Don’t overdo the watering, but provide as much humidity as possible.
If the plant is overgrown but the mix is still acceptable, a procedure called “dropping on” is useful. Remove the plant from its overgrown pot and place it, mix and all, into a larger pot. Then add the fresh mix to fill gaps. Dropping on disturbs roots very little and is an acceptable way to re-pot even at proper times if the mix is still good. Orchids that prefer a somewhat decayed mix (such as Cymbidium) do better being dropped on, with a full reporting only every other time.
Another useful trick for overgrown sympodial plants climbing over the side of the pot is to place another same height pot next to it to accommodate the overhanging pseudobulbs and roots. The second pot should be plastic so that you can cutaway a V-shaped section of the rim so it will fit better under the overhanging growths. Position the second pot under the new growths and roots hanging over the side of the other pot, and fill it with the new mix. Then tape the two side-by-side pots together around both rims, to prevent the new pot from moving. The overgrown parts can establish in the new pot without too much disturbance. When the proper time arrives, the entire plant can be reported into a larger pot, or easily divided, with a natural break at the point between the two pots.
Another time you should avoid reporting your orchid is when it is in bud or flower. Wait until flowering is over because re-potting can cause enough trauma to make the flowers or buds drop off. If the orchid has a flower sheath with no buds evident inside, or if the spike is still short and bud-less, feel free to go ahead if necessary. Newly acquired plants may require reporting if the mix is obviously deteriorated or the plant is overgrown. However, give new plants at least a month to acclimate themselves to their new growing conditions before re-potting, to allow recovery from the trauma of a new environment without the added trauma of re-potting.
Spreading Virus, Disease, and Pests
Because of all the handling and cutting that goes on during re-potting, and because people usually re-pot more than one plant at a time, the probability of passing virus, disease, and pests between plants is very high. The wisest course of action is simply to assume that every plant is a virus. Use plastic disposable gloves, changing them between plants or at least washing them. Don’t use your bare hands. Re-potting is a sloppy operation; fingers tear away rotten roots or break off old pseudobulbs, and even with washing, plant pieces can remain under your fingernails, ready to infect. Gloves eliminate many variables, and they protect hands from splinters or possible pathogens in the medium.
The other primary source of infection during re-potting is the cutting instruments. Never use a cutting instrument on one plant and, then reuse it on another without first sterilizing it between plants. Sterilize tools by using a propane torch flame or by soaking the tools in a trisodium phosphate solution. Dipping tools in chlorine or alcohol will not sterilize them enough to kill viruses. An easier solution is to buy packs of single-edged razor blades and use one for each plant. Blades can be cleaned and oven-baked at 375°F for an hour to sterilize.
Reusing Potting Materials
If the material is still in good shape, you can reuse it with no problem for the same plant in a different pot. But never transfer a used potting material from one plant to a pot of another orchid. This is sure to transfer pestilences. The best recourse with an old organic mix is to resign it to the compost heap. New clay pots have been oven-dried, so pre-soak them in water for half a day to fill pores. Older clay pots that have been washed and dishwasher-dried also need pre-soaking.
To clean clay pots encrusted with leached salts and algae, soak them in hot water for several days, changing the water a few times. Then scrub with steel wool in warm water with dish detergent added. Adding a little vinegar to the soak water helps loosen salt deposits.
In order to kill any virus present on clay and polypropylene pots, pots must be subjected to a temperature of 180°F for 30 minutes. Some high-temperature dishwashers get this high, but most don’t. A safer way is to soak the pots overnight in a 9:1 water/bleach solution. Then rinse and soak them in plain water for 15 minutes, rinsing again before using. Baking in a 200°F oven is also possible; polypropylene pots have a melting point of 250°F.
Nuts and Bolts of Re-Potting
When you’re ready to re-pot, first choose a convenient work-space. A spot near a sink and a trash basket is good enough. If there’s no counter space, place a piece of the board across the sink. Put lots of layers of newspaper down on the work-space, especially if you are re-potting more than a couple of plants at a time. In between each plant, the mess can be bundled up in some of the newspapers and neatly disposed of, leaving a clean layer on which to proceed.
Have on hand new or sterilized single-edged razor blades, a box of disposable plastic gloves, a knife, various sizes of clean pots, plant stakes and ties, rhizome clips, and some way to clean the knife in between plants (trisodium phosphate solution or propane flame). A toothbrush is also handy for ridding plants of insect pests. On the floor have a bucket of potting mix soaking in warm water, preferably overnight.
Soak each orchid and pot in a bucket of water for a few minutes; this makes it much easier to convince the orchid to leave the pot. Also, the roots will be softer – more pliable and less apt to break – and will release somewhat their often tenacious grip on the inside of the pot. Roots and plants are likewise more pliable when re-potted after time in a warm rather than cold environment. Hold one hand over the top of the mix and turn the pot upside down. Some plants slip out easily onto the newspaper layers. If the orchid resists, tap the pot sides and bottom, or gently squeeze a plastic pot in various places. If the orchid really clings to the inside of a plastic pot, take a sharp sterile knife and run it around the inside wall of the pot. If the roots are stubbornly clinging to a clay pot, you may have to break the pot by turning it on its side and tapping gently with a hammer. If bits of clay hang on the roots, don’t remove them, as that will break the root.
If the orchid is being re-potted because of a deteriorated mix rather than overgrowth, you can reuse the same pot. Otherwise, set the used pot away and don’t use it for another orchid until it has been sterilized.
Taking a Look at the Roots
Now is an excellent time to pause and take a good look at the potting material, to glean invaluable information about how well it has responded to watering techniques and the environment. Even more important, take a look at the roots. Let them be the guide to how well a potting material is working. Live roots are usually white, glistening, sometimes green-tipped, and firm to the touch; these are indications of an excellent mix for the conditions. Dead roots are gray, brown, or black and soft, mushy, or dry to the touch. Decaying roots can be something in between.
If the roots are soggy, mushy, or black, the mix is not draining well enough, nor is it aerated enough for the watering technique and environmental conditions. The time between re-potting may have been too long. If the center portion of the root ball is dead but roots at the edge of the pot seem fine when too much water is staying in the mix. Either the potting material itself holds too much water, or you are watering too often. Desiccated gray roots point to an over dry mix. Roots with black tips can be an indication of too many salts, often caused by over-fertilizing or softened water, or even snail damage.
Remedy the errors by fine-tuning the mix. To make the mix drain better, add materials with less moisture retention, such as charcoal, rocks of some sort, tree fern, coarser bark, perlite, a clay pot. To retain more water, add sphagnum moss, rock wool, finer bark, a plastic pot.
While the Plant is out of the Pot
Clean away all of the old potting material, but try not to break any good roots. The center of the root ball often will be the most decayed. Shake off the mix, pull the root ball gently, and run the orchid under tepid water. Cutaway dead roots up to the base of the orchid. To confirm which roots are dead, hold them one at a time and pull gently; if the outer portion slips off easily and a wiry core thread is left, or if the root is brown all the way through the center, the root is dead. Partially decayed roots should also be cut away to a place where fresh tissue starts. If the roots are dead, soft, and mushy, suspect a root-rotting fungus in the mix, and after cutting away rotted parts, treat what’s left with powdered sulfur. Try to keep as much of the good root system as possible.
If some roots are extremely long and difficult to get into a proper-size pot, trim them. Trim only thick roots that are covered with white velamen. Don’t cut away thin, wiry live roots, for these won’t form branches like the thick ones can if cut.
Trim off dead or yellowed leaves, old flower spikes and sheaths, and dried-up or rotten pseudobulbs. If an otherwise live-looking pseudobulb has no leaf, don’t remove it, particularly if good roots are attached, for it still stores some reserves of food for the orchid. When cutting away rot, dust the remaining part of the pseudobulb or the leaf with a sulfur fungicide to help keep rot from spreading or recurring. Search the plant for insect infestation such as scale or mealybug, which can hide on roots, under sheaths on pseudobulbs, and in the crown of the orchid. A toothpick can be useful in searching down leaf sheaths. If pests are discovered, use a soft toothbrush and tepid water with insecticidal soap to very gently clean the orchid.
Preparing the Pot
The drainage holes must be protected from becoming blocked – particularly important in a clay pot where there is usually only one hole. The most popular arrangement is to cover the bottom of the pots with large pieces of broken pots, polystyrene, stones or other similar material. These are termed crocks. They should be larger than the smallest drainage holes. Arrange the top of the crocks into a slope. This will enable gravity to drain the capillary water that would otherwise be held at the drainage interface between the crocks and the growing medium. Do not put in more crocks just to reduce the volume of the growing medium. Better to put a small inverted pot at the bottom with pieces clipped out of the rim. This will have the benefit of providing an air space in the very area which is the last to dry out. Roots often rot in this area. Contrary to what may be thought, a test will show that extra crocks do not significantly shorten the time taken for water to drain through the pot if the drainage holes are not blocked.
Positioning the Orchid
Positioning depends on the type of growth an orchid makes. Horizontal growers need to be placed so that the back end of the orchid touches the wall of the pot, with the space in front of the newest growth for future spread. If such a plant has symmetrical growth, with no back end apparent, leave the same amount of room all the way around the plant.
Monopodial orchids that grow upward should be set right in the center of the pot. Position the orchid in the pot before adding mix so that the rhizome or crown will eventually sit about 1/2 inch below the pot rim. It’s not necessary to stuff all the aerial roots back into the pot, but spread out the pot roots in the pot as much as possible. Hold the orchid in place with one hand, and start adding mix. Always stir the mix before using it, for the various ingredients will settle differently over time, depending on weight and volume.
Pour-able mixes such as bark-based or tree fern can simply be filled in about a third at a time; tap the pot gently on the work surface with each addition, so that mix can settle without huge gaps. Materials such as sphagnum moss and rock wool don’t settle and must be arranged in the pot, so use gloved fingers to push the medium around. Make sure not to pack either one of these too tightly. Osmunda can be packed tightly. The way the “grain” of osmunda or sphagnum moss lies will also affect how much water the medium will hold.
The horizontal plant rhizome of a sympodial orchid is part of the stem rather than a root, so it should not be covered by the mix. Allow it to lie half in and half out of the mix. The monopodial basal crown of leaves in plants such as Phalaenopsis should also not be covered but should lie instead just on the mix. Positioning the crown too low, below the mix, will invite rot, and positioning it too far above the mix will cause the orchid to over dry.
Once the orchid is potted, it may need stabilizing to prevent wobbling, when new root tips can be damaged or broken off. One way to add steadiness is by placing stones on top of the mix. Even better is to stake the plants upright. Any number of traditional plant stakes are available, wood or metal (more about staking below).
Watering the orchid right away after re-potting does help settle and firm the mix. And while there is no hard evidence as to its real benefit, many orchardists swear by the addition of a few drops of vitamin/hormonal additives such as Super Thrive to the water at this time to help give orchids a good start.
If the environment is very humid, simply misting at re-potting is fine. If you have a relatively dry situation, water. After that, do not water the orchid thoroughly for several weeks. Instead, give it light misting every day, just to stimulate root growth. Orchids with root systems that have been badly decayed or damaged won’t be able to take up much water through the roots, so they are dependent on what the leaves can gather, and a light misting helps them immeasurably. The larger pot with more mix will be holding more water than usual anyway, so it’s better to keep the orchid on the dry side for a while to avoid rot and to allow cut edges to heal. As the roots get longer, eventually going into the mix, begin regular thorough watering again.
It’s often beneficial to put the orchid in a slightly more shaded place for the first week after re-potting, although opinion differs as to whether this is really necessary. In any event, it probably helps to keep the orchid out of direct sunlight at first, moving it back gradually. Also avoid putting a newly re-potted orchid in a cold damp place, especially one with bad air movement.
Specimen Plants versus Division
The biggest and most abundant flowers will be found on a plant that is allowed to keep on growing, being moved to a larger and larger pot with each re-potting. Another cultural trick for growing a specimen plant is to rotate the pot or mount every few days so that all sides of the orchid continually receive equal amounts of light. This helps develop growths and flowers all over the orchid, rather than in a single orientation.
A Primer of Potting
Even if you eschew propagation in favor of purchasing full-size orchid plants, you’ll eventually be faced with the need to re-pot some of your collection. Following the flowering season, and before new growth breaks, there is usually a period of 2 to 6 weeks that is optimal for re-potting orchids. The orchids are then in their most dormant stage when the necessary root disturbance will be felt the least. It is also possible to transplant successfully somewhat later when new growth is 1 to 3 inches long.
Orchids growing in 5- to 8-inch containers usually need re-potting when the plants have begun to outgrow their containers and the planting medium has started to “break down” and lose its open texture. Larger orchids (in larger containers) should not be disturbed for several years or until the potting material starts to lose texture. The new container you choose should be large enough to allow for 2 years’ growth, but no more; this usually means a pot approximately 2 inches wider in diameter. Keep in mind that orchids do best when they are slightly crowded.
Most epiphytic orchids are potted in fir bark, which is inexpensive, comes in a variety of sizes, and breaks down slowly. The orchids take nutrients from the bark as it slowly breaks down, somewhat as a time-release fertilizer capsule releases its nutrients over time. The finer the bark particles, the faster the nutrients are released. As those particles decay, they also tend to pack together, reducing air spaces and thereby slowing drainage. Fine grades are used for seedlings or small orchids with fine roots; they are also combined with other ingredients to make up mixes for terrestrial orchids such as cymbidiums. Larger grades are used for mature orchids. The large air spaces between bark fragments ensure excellent drainage; however, bark’s slow rate of decay means that the medium furnishes little nourishment, so frequent feeding is necessary.
Chunks of coconut fiber are somewhat similar to fir bark, but they retain water longer. This medium is far less common than fir bark, but it is plentiful in tropical areas and obtainable by mail in others. (Shredded coconut fiber is being used in some areas in place of sphagnum peat moss, an increasing scar, and ecologically threatened commodity.)
- Charcoal chunks – are useful for absorbing excess fertilizer or contaminants and for improving aeration, but they, too, are seldom used alone. Added to other materials in a 1-to-10 or 2-to-10 proportion, they can help maintain a healthy medium.
- Coconut-husk fiber – This by-product of coconut processing is relatively plentiful and, when dry, quite lightweight so that it can be shipped efficiently. The pale, reddish-brown color flatters the green of orchid plants and looks attractive in either clay or plastic pots. It works well as the sole medium for epiphytic orchids and is slow to decompose. Balanced fertilizers such as 23-19-17 or timed-release 14-14-14 work well with coconut fiber.
- Cork – semi deteriorating; organic. Holds little water. Water 2 x/week. Re-pot every 3 years. Mounts last many years. Use 20-20-20 fertilizer with trace elements.
Cork is the most popular slab material for orchid mounts. Thick, lightweight bark from the Mediterranean cork oak is boiled and used as “nuggets” for potting orchids. Cork is inert, providing no nutrients. When the cork is utilized as a main potting ingredient, charcoal is almost always added (60:40). Cork is sometimes used as an additive. Although its decay is slower than that of fir bark, cork is prone to millipede infestation, which turns it quickly to slush.
- Fir bark – deteriorating; organic. It holds 80% of its weight in water. Water 1 x/week. Re-pot every 1-2 years. Use 20-10-10 fertilizer. pH = 5.0.
Fir bark is the most widely utilized potting material, easy to use and obtain, a timber by-product from American evergreen firs. Deeply furrowed Douglas fir is preferred. Pieces are sized coarse, medium, and fine. The smaller the size, the more water is held and the faster the decay.
Fir bark is steam-treated and kiln-dried to remove resins, making it difficult to wet at first. Pre-soak it in warm water for 24 hours, until the pieces float. With use, decay begins; the mix turns to mush after 2 years. Beginners often err by waiting too long to re-pot a bark mix. Re-potting annually staves off many problems.
Additives help, keep the mix open. A common mix is fir bark, redwood bark or wool, peat, and perlite, in varying ratios, such as 7:1:1:1. Stone or expanded shale also helps ward off compacted decay.
Many people mistakenly believe that a high-nitrogen fertilizer is necessary for orchids no matter what the potting mix, but this is wrong. It’s just for orchids in bark. The bark is broken down by a common wood-rotting fungus that also consumes a lot of nitrogen. Therefore bark-potted orchids need a high-nitrogen fertilizer, such as 20-10-10, to give extra nitrogen for the fungus.
Even though 30-10-10 has long been touted for orchids in the bark, this too-high nitrogen ratio encourages the growth of leaves at the expense of flowers and causes soft, fast-growth prime for pest attack. Use 20-10-10 instead.
- Charcoal – Hardwood charcoal (not pressed-powder briquettes like you use for barbecuing) is added most often to cork or redwood bark, both of which produce a lot of acids. Charcoal absorbs the acids. It is also a common component of commercially packaged mixes. Like lava, charcoal collects salts, so don’t use it if you have hard water.
- Lava rock – and gravel do not break down at all, and they promote excellent aeration around roots – but their rapid drainage rate means you must attend faithfully to your watering. Lava rock and synthetic rock nodules retain water better than gravel does. These materials have no food value, so orchids grown in them will need more frequent feeding. On the plus side, their weight makes containers more stable and less likely to fall or blow over, and these media may be sterilized and used again.
- Man-made mediums – These include a variety of products made from clay or shale that have been fired to form nuggets of a porous material similar to lava rock. Expanded clay is most commonly used in Hawaii, with a balanced fertilizer such as 20-20-20.
- Osmunda – the tangled, matted roots of several species of ferns – was once the favored medium for epiphytic orchids, but it is now scarce and expensive. It breaks down slowly, retains some moisture while allowing free access to air, and has some food value. Although many experts still favor its use, beginners may find it harder to manage.
- Peat moss – Peat moss has an even greater water-holding capacity than sphagnum, but it decomposes more rapidly. Coarse peat was once a favorite ingredient in orchid mixes, but it has become scarce and expensive and is now rarely used. It should not be mixed with tree fern, cork, or osmunda fiber, but maybe blended with fir bark or charcoal. Coarse peat moss contains few nutrients and breaks down slowly, so balanced fertilizers are recommended. Horticultural peat is too fine and dense for orchids.
- Perlite – or sponge rock, is seldom used alone but is a frequent element in blended mixes. It is lightweight and offers excellent retention of air as well as water. Vermiculite is similarly water-retentive – too much so to be used alone, but useful in some mixtures for moisture-loving species.
- Polystyrene foam (StyrofoamTM, Aerolite, Packing Peanuts) – non-deteriorating; organic. Nonporous. pH = neutral.
Polystyrene foam is a light, white, durable solid plastic with closed foam pores. It is sometimes used as an alternative to perlite, especially when crumbled, to aerate and open a mix, typically at the pot bottom to improve drainage.
Other foams can be confused for polystyrene; porous types such as polyethylene and polyurethane absorb plant-damaging salts. Some foams are chemically treated, releasing toxins. Packing peanuts shaped like little binoculars are made of soluble cornstarch and dissolve into obstructive, disease-ridden sludge when used for potting orchids.
- Redwood bark (Redwood Wool, Palco Wool) – deteriorating; organic. Holds 50% of its weight in water. Water 1 x/week. Re-pot every 2 1/2 years. Use 20-10-10 or 20-20-20 fertilizer. pH = 3.5.
Redwood bark is the thickly furrowed, fibrous reddish bark of the Californian sequoia tree. Unlike fir, redwood has no resins, has lower pH, and decays more slowly; less nitrogen is thus needed and 20-20-20 fertilizer is adequate.
Since redwood bark is expensive, it is used mostly as an additive, usually to fir bark, and is also available as a more absorptive fibrous “wool.” Redwood bark is used more as a main ingredient in areas of high heat and light, such as Florida, where it outperforms fir. Charcoal is generally added.
- Rock culture – inorganic rock culture for orchids is often a more successful alternative to bark in decay-prone and/or over-watering situations. Stones, lava rock, and expanded shale pebbles are the three basic materials. When added to deteriorating mixes, they provide good air space. Use plastic pots for the best results.
In rock culture, the medium does not decompose. Re-potting is needed only when the pot gets too small. It does, however, mean growing virtually hydroponically; the grower must provide a complete, balanced fertilizer with trace elements, and water quality and pH also become important.
- Sand (Builder’s Sand, Sharp Sand) – non-deteriorating; inorganic. Absorbs 20% of its weight in water. pH = neutral to 4.3.
Sharp sand is the quartz or silica part of the soil, found in gravel pits, not on beaches. The coarser the particle size, the better (1/16 in. or more). This is a good terrestrial mix additive for drainage and aeration. It is never used as the main ingredient.
- Soilless mixes (Premier Pro-Mix BX, Metro-Mix, Fisions Sunshine Mix #4, “Mud”) – semi-deteriorating; organic/inorganic. Water 2x/week. Repot yearly. Use balanced fertilizer. pH = 5.5-6.0 (changes over time).
These various commercially available prepackaged mixes are usually some combination of sphagnum peat moss, vermiculite, sometimes perlite, and granular nutrients such as dolomitic limestone, superphosphate, calcium nitrate, and potassium nitrate. They can be tricky to learn to water properly, and they decay rapidly and thus are better used for moisture-loving seedlings and Phalaenopsis, although soilless mixes in clay pots work well for orchids that need more drying (for example, Cattleya).
- Sphagnum moss – live or dead, is especially useful in maintaining surface moisture for delicate roots. For that reason, it is often used to wrap the roots of orchids mounted on trees or bark slabs. Live (green) sphagnum seems to have some antibiotic and fertilizing value: New Zealand and Chilean sphagnum are the favored kinds. But beware: hard or chlorinated water will kill live sphagnum; use rainwater or deionized water with it.
- Tree fern fiber – the dark, spongy, porous material used as “totem poles” to support philodendrons and similar house plants – is a well-aerated, moisture-retentive growing medium. It may be sliced into slabs for packing around roots, or orchids may be attached to large pieces, which their roots will cling to or penetrate. Where tree ferns are common, whole sections of trunk are often hollowed out and used as pots.
Most orchid enthusiasts grow their orchids in pots, usually of clay or plastic: each type has its advantages. Plastic is lighter in weight and loses no moisture through its sides, thereby lengthening the period between waterings. One advantage of clay pots is that their porous walls improve aeration around plant roots and – by means of evaporation from their surfaces – keep the roots cool. Their greater weight, too, helps keep top-heavy orchids from falling over.
Some pots have a single hole at the bottom; others have slotted or pierced sides for faster drainage. The most important criterion for any container is that it provides quick and complete drainage. Water must penetrate quickly, and air must follow the water-otherwise, the roots may deteriorate.
Those who find ordinary pots unattractive may purchase handsomely formed and glazed pots that have been designed especially for orchids. But homely pots can always be hidden inside of ornamental pots or baskets for display on the coffee table, with a thin layer of sphagnum moss on top for added disguise. Be sure, in such arrangements, not to allow the inner pots to stand in water that has drained into the decorative shell.
Wooden baskets provide extra-fast drainage for those orchids that need it; these may be suspended horizontally or for orchids with trailing or hanging growth-vertically. Slat bottomed baskets or rafts are essential for orchids like Stanhopea that send their inflorescences downward rather than upward. Orchids may also be mounted on slabs of cork bark, segments of small tree limbs, or “totem poles” of tree fern stem.
Your first order of business when potting orchids is to make certain that your containers are absolutely clean. Clay pots and the broken clay shards used for drainage purposes should be scrubbed in scalding water or a 5-percent bleach solution before use. If you are planning to use osmunda, first soak the medium overnight before cutting it into 3-inch squares.
When transplanting to a larger pot, removing a plant from its old container should be done with care; live roots may be damaged if you attempt to pull out the plant by force. Soak the plant in its pot for a few minutes, and let it drain thoroughly. Then gently tap the outside of the pot with a hammer or invert the pot and strike its edge against a tabletop, turning it as necessary.
Clean out any old leaves and flower spikes and be sure the orchid is free of insect infestations. If you want to divide your orchid, now is the ideal time.
- POTTING IN CONTAINERS. Where you place your orchid in its new pot will affect how it grows. Sympodial orchids should be placed with the oldest pseudobulbs close against the rim of the pot and with the bases of the rhizomes approximately 1/2 inch below the rim; the bases of the newer pseudobulbs should be parallel with the bottom of the pot, even if this means placing the whole plant at an angle. Monopodial orchids should be centered in the pot, with the bottom of the lowest leaf about 1/2 inch below the rim, just at the surface of the potting material.
Set the orchid in place, spreading out its roots. Aerial roots that can easily be bent down into the pot should be covered by mix; others may be permitted to remain above it. Then fill in around the roots with fresh potting material, occasionally pressing it down with a blunt-edged stick. Osmunda fiber, in particular, should be tightly packed around the roots. Work from the sides of the pot to the center until you have filled the pot to within a half-inch of its rim.
- PLANTING IN BASKETS. When preparing baskets to receive orchid plants, line them with a thin layer of sphagnum and then set the plants in place as you would in an ordinary container. Ensuring adequate drainage is no problem in basket planting.
- PLANTING ON SLABS. If you plan to grow your orchid on rafts or slabs of wood, bark, or tree fern, place the orchid with its roots against the slab and cover them with sphagnum moss. Tie this root ball to the slab with galvanized wire, string, monofilament fishing line, even old pantyhose; or fasten it in place with electrician’s staples. Keep the root ball moist; when roots appear to have securely anchored the orchid to the slab, you may cut away the ties.
Although staking may be no more than a common-sense means of protecting a developing spike of orchid flowers while the plant is in transit, it can also be a happy marriage of art and science that results in a subtly more beautiful presentation at flowering time. Orchid growers use galvanized wire stakes in a variety of configurations that come preformed to suit the habits and various sizes of the most commonly cultivated orchids. Three types offered for sale where orchid plants are sold include:
- A length of straight wire, usually 12 to 18 inches long, with its top bent into a U-shape. The “U” holds the flowering spike and the effect of the stake is based on its depth, angle, and positioning in the growing medium.
- A wire with one end shaped to clip over the rim of the pot, above which a length of straight wire-usually about 5 to 8 inches tall – extends. The upper end of the wire is formed into a circle that can be from 4 to 5 inches in diameter or up to 8 or 10 inches across. This circle is intended to cradle several or many mature growths of cattleyas and similar orchids.
- A wire pot clip, which is hardly more than a horizontal length of wire, usually 4 to 8 inches long, with bends in one end to clip over the pot rim. This simple piece of equipment is used primarily to secure sympodial orchids after they are first potted until the roots become established.
Another type of stake used by commercial growers is bamboo, which can be thin and reed-like or as thick as a pencil. Sometimes these stakes are inserted only to protect the orchid during shipping. On other occasions, the bamboo cane that comes with a purchased orchid needs no further dressing other than to have utilitarian plastic ties or twist-ties removed and replaced with the more graceful and replaced with the more graceful and organic raffia. Be gentle when tying the orchid to the stake. Use a figure-eight tie, first wrapping the raffia tightly around the stake, then loosely around the orchid stem.
Besides wire and bamboo, a third material for staking orchids can be found in most yards, namely twigs from trees and shrubs. Often these can be cut and trimmed so that a “Y” or “U” already present in the branches can gently cradle and hold the orchid spike to show off its beauty to maximum advantage.