Phalaenopsis Cultural Notes from John Simmons, member of Noosa & District Orchid & Foliage Society.
Since Phalaenopsis (Moth Orchids) have no pseudobulbs or other water storage organs, they don't like to dry out too much. It's best to water as they approach dryness, usually about twice per week. Of course, the easiest way to kill an orchid is through over watering, so don't keep them constantly too moist or the roots will rot and you may also see other orchid diseases!
To water a Moth Orchid, take it to the sink and run water through its pot until it
When a Moth Orchid is done blooming, the flower stems will sometimes re bloom in future years. As long as the stem remains green, this is a possibility. If the stem turns brown, you should prune it back. You can also sometimes trick the plant into re blooming right away if you cut the stem back just as the plant finishes blooming: cut the stem about an inch (2-3cm) above one of its nodes, which are small scale-like leaves you'll see on the flower stem if you look closely.
Phalaenopsis prefer intermediate-to-warm temperatures of 70-85°F (21-30°C) during the day, ideally with a night-time drop of 10-15°F (6-8°C). Be aware that temperatures above 80°F(27°C) can signal to the plant that it's not the right season to bloom. If the temperature is comfortable for you, it's probably comfortable for Phalaenopsis too. To keep humidity high use a mist spray regularly as Phals love this.
Ken McGregor has a fine reputation for growing and flowering Phalaenopsis. I’ve asked him many times about how he grows them so well. A few things must have stuck, because my Phals flowered well in the spring of 2019. They then really struggled through our recent summer. I repotted them in March with new mix and a clean out of the heat-damaged roots that I thought would become rot-susceptible. In a few socially distanced weeks they responded with vigorous leaf and root development and most of them now have fast-developing flower spikes.
Have a great week.