Rehabilitating a Sick Orchid
Due to their resurgent popularity, many varieties of orchids are now available in garden centers nationwide. Perhaps the most common single brand, which is even readily available at Lowe's, is Better-Gro. They sell small and medium sized plants for very competitive prices, and even though they might not yet be blooming size, they are a bargain for the cost and raising them yourself can be a rewarding experience.
However, even though I have no doubt that these plants are in good condition when they leave Better-Gro's greenhouses, once they endure their fateful voyages to their retail locations, and spend a couple weeks on display, they are not looking nearly as good. It has been my experience that the stores I have found them in by and large do not water the plants at all, so if they are out more than a very short period of time, they have become dessicated and sick, so great care must be taken to select a good quality specimen. Obviously look for any major flaws like blackened, soft, or dying sections of the plant, as this can sometimes mean that the whole plant is in danger, but also try to see if there are any visible roots, and whether they have a green tip on the end or if they are soft and papery. Looking out for pests is another major concern, since they can easily hop to other plants in your home, as well as sicken the plant they are on.
The most common pests on commercial orchids are scale insects and spider mites. Both of them can appear on any part of the plant, but they both also have their own "special" areas which they prefer. Scale insects will usually appear to be small white or brown circles, usually only a millimeter or less in diameter, that form clusters around the bases of leaves. They can be easily scraped off with a fingernail, and have a papery consistency (as in the case of the white ones), or a brittle, crumbling consistency (as in the case of the brown ones). Once a plant has scale insects, they can be very difficult to eradicate, so it is better to just avoid a plant that is already infested. spider mites will form small nests on the underside of leaves that have the appearance of spiderwebs or cotton, usually within curls or other semi-hidden areas. They are easier (in my experience) to get rid of, but also spread to other plants much more aggressively. I had a plant that had a small colony of spider mites that I put next to a group of other plants, and within a week six other plants had gotten them as well. It took over two months to eradicate them because they kept spreading. Better, again, to avoid any plants that have evidence of their presence.
The worst surprise when buying a new orchid, however, is to take it home only to realize that their root systems have been compromised. For this reason, it is always best to select a plant that has evidence of new leaf growth, as roots will more readily emerge from these areas. Leaves on most sympodial orchids (such as Cattleyas, Epidendrums, Brassavolas, and their relatives) will appear as small green cones that are coming out from the bases of the outermost leaves. This is why I recommend that as soon as you buy a new orchid, you should immediately douse it in the sink, remove it from its pot, and inspect the roots. When wet, healthy roots appear green and thick, with small white specks running down them. Unhealthy or dead roots will be brown, soft, and papery. These should be cut off with sharp shears. Take care not to damage any healthy roots, however, since even the slightest bump against the growth tip (a soft, fleshy, bright green point) can cause it to stop growing. Often the potting media will be decayed or moldy, so it is best to discard it and plant the new plant in fresh media to begin with.
As an example, I recently purchased two specimens of Rhyncholaeliocattleya Ports of Paradise, labeled as Blc. Ports of Paradise. It is labeled Blc. because Better-Gro still uses an older nomenclature system where a plant used in this hybrid, formerly labeled a Brassavola, was reclassified under a new genus, Rhyncholaelia. After soaking the plants, I noticed a very strong mildew odor emanating from them, and after I removed them from their packaging and their pots, I saw, to my dismay, that their roots had been completely destroyed and the potting media was riddled with mold. However, I had bought them with new leaf growth, so I was not completely crestfallen. This is a danger that has become real for me for roughly 50% of the plants I have bought since I started collecting them, however, so it does not necessarily mean a death sentence. In fact, most of the plants I have lost over the years have been due to fungal, pest, or cold or heat exposure issues, so lack of roots does not necessarily indicate a death sentence.
When you buy a plant with sick or dead roots, it is very important to get it into a healthy environment as soon as possible. Many people will put the plant in a gallon-sized zip-lock bag with either damp sphagnum moss or moistened and squeezed paper towels, and then inflate them with breath before sealing them and putting them in a warm and bright location. I have had some success with this method, but I have found that mildew or algae growth within the bag can occur very quickly and can create a very severe shock for the plant.
My preferred method is to utilize a fish or reptile tank. This can be any size; I have an "intensive care" tank that is a 10-gallon tank, but I also have a lot of smaller and more sensitive plants in a 50-gallon tank. I will clean the tank thoroughly with bleach, and then pour in aquarium stones, also washed in bleach and rinsed well, to line the bottom. The stones will hold water to maintain humidity without creating dampness or dankness. Then, after putting the plant in a small pot with loosely packed sphagnum moss, I'll seal the tank. In my experience, "85-85" is the ideal environment; 85 degrees Fahrenheit, and 85% humidity. When I kept my Vanilla vine in this tank, kept under these conditions, it was growing about a centimeter a day. Additionally, you can place a "sunlight" spectrum CFL bulb, as long as it is not too bright, directly over or against the tank to provide the much-needed light and warmth. When I was rehabilitating the Vanilla, I had the light on 24 hours a day. With other plants, I've tended to switch the light on when I woke up, and turn it off when I went to bed.
It is important, even with the sterilized tank, to be ever-vigilant for any sort of mold, mildew, or any other contaminant. Algae can form anywhere in such a humid and warm environment, but most often it will form on the top layer of the sphagnum moss. Despite having a sometimes surprising appearance, it is mostly harmless. It consumes water and nutrients and, in that sense, can be seen as "competing" with the plant, it will not actually harm the plant. Mold, on the other hand, can destroy even a healthy plant in days. For example, I had some sort of red fungus form on the roots of my Neostylis which completely eradicated them in less than 36 hours. Small breakouts of mold can be treated with a cotton swab and some alcohol; I usually have a small bottle of everclear for this purpose. I'd recommend against using bleach, since that can easily burn the roots. High-proof alcohol is volatile enough that it will evaporate more quickly than it will be absorbed.
As long as you can create a mold-free environment with good humidity and avoid excessive dampness, don't give up on your sick orchid. I had a Phalaenopsis that had lost all its roots and its leaves were soft, wilted, wrinkled, and purple, but I was able to bring it back to life using the methods outlined above. Orchids are surprisingly resilient plants, and you will probably be surprised how much they can recover from.