Our orchids have ways of telling us that something is wrong. My Oncidium Twinkle is having a few problems at the moment, and finding out what is causing these problems is making interesting reading.
Since last October, this orchid has been displaying signs it isn’t happy, by developing strange markings on its leaves. These include brown marks that seem to sit in the crease of the leaf, and also some slight discolouration. The brown marks do not wash off, and are now part of the leaf tissue. The newest growths appear to be the worst affected by the brown marks, whilst the older leaves are demonstrating the discolouration.
Overall, this is beginning to make this orchid look scruffy. Combine this with the wrinkling pseudo-bulbs and we are looking at something that is borderline unsightly.
After doing some reading and research online, as well as contacting the nursery I purchased this orchid from, I can now start drawing some conclusions. The Oncidium Twinkle has mild cold damage.
In our previous home, she was kept on a windowsill that had low light levels, but also lower temperatures. Together with daily misting, and limited air flow, this appears to have caused some cold damage over winter. Water accumulates on the leaves and the low temperatures cause the cells to collapse, becoming brown or black in colour where the water has been. Young leaves are more susceptible to cold damage than mature leaves – which makes sense. The brown markings are happening more on the younger leaves of this orchid.
So, how do we prevent cold damage from happening? It’s simple. In the colder months, keep your orchids at a temperature that they can handle. It’s perfectly fine to mist orchids that are within their temperature range, so long as you do not allow water to accumulate i.e. in the crown of a Phalaenopsis. However, a significant drop in temperature puts your orchids at risk of developing rot or cold damage. Oncidium type orchids are a little fussy compared to Phalaenopsis orchids, and as such can be more challenging to care for.
Also, always use room temperature water on your orchids, even in summer. Cold water can shock them, and also increases the risk of cold damage on leaves. If you notice your orchid has cold damage, do not move it somewhere that is several degrees warmer instantly. The increase in temperature must be done slowly, so as not to cause further stress to the orchid.
Hopefully, by following the above, the likelihood of cold damage happening again will be reduced. No matter how long you have been in the orchid hobby, I’m sure there are always new things to learn!