As a general rule, orchids should be planted on a soil that has been slightly warmed. Most reputable orchid growers insist on this prerequisite, since exposure to high temperatures can damage the delicate state of their plant orchid roots. They will also prevent your orchid from freezing during its growing season. Orchids thrive in a fairly cool (around 55 degrees Fahrenheit) environments, and they will do well in pots where the potting medium has been soaked in warm water prior to use.
Many orchids suffer from a fungal disease called Phytoseiia impati. This is a brownish or yellowish spot on the leaves and stems, and it’s an aggressive fungal infection. The stem area eventually thins and drops off, and then dies. It tends to attack newly planted orchids, but if you’ve grown your orchid plants for a while without incident, it probably hasn’t encountered Phytoseiia impati. Phytoseiia impati, like so many other types of fungi, attacks other plant species as well, including tomatoes, peppers, squash and melons. It particularly hates orchids, which is one of its primary reasons for developing the disease.
You might find that your growing orchid plants have contracted Phytoseiia impact if they suddenly seem less vibrant or have unusual stem shapes or growth. You may even notice that some of the roots have white spots. These are the origins of the fungi attacking your orchid, and they need to be taken care of right away.
When the orchid fungi attack your orchid plants, it doesn’t mean that your orchid has fallen ill. It simply means that there is a fungal infection. In order to treat the infection, you need to get rid of the Phytoseiia impact that is attacking your orchids. You can take care of this by applying a fungicide directly to the orchid roots. If you are growing orchid plants in a pot, you should direct the spray to the plant only, since the roots of the plant will absorb some of the spray.
Before you do that, however, you should water the orchid a few times, to help loosen up the roots of the orchid. Then, go ahead and take out your hand and gently grasp the bottom of the pot. Tap the bottom of the pot firmly a couple times, so as not to damage the roots of your orchids. Do this several times. This should remove most of the fungus from the orchid roots.
Once you’ve gotten rid of the fungus, you should move on to killing the orchids that have been damaged by the fungi. In most cases, this will be easy, since orchids are easy to kill with the use of a sharp knife or pruning shears. You can use these tools to trim away any of the dead orchids, and once they’re dead you can simply drop them into a medium such as a compost pile. Make sure you place the compost pile in a dark, dry place, because the roots of your orchids could take many years to grow back if they’re planted in a light and moist soil. However, once you’ve established your orchids in a new compost pile and they’re growing nice and well again, you can report them and give them another try.