I received a moth orchid as a gift a couple of years ago. It was blooming at the time, but nothing since then. How do I get it to bloom again? – Sarah M.
Orchid experts say that the moth orchid – phalaenopsis – is the easiest and best for non-experts and beginners, since they tend to do well in average home temperatures and conditions. At the Web site of the American Orchid Society the experts say that insufficient light is the most common reason an orchid fails to re-bloom. That’s general information about all orchids, but here are more specifics about phalaenopsis:
They grow well in a bright window – an east window is ideal, south or west window if you provide a little shade. The main blooming season for moth orchids is late winter into spring.
Moth orchids like it warm. Temperatures should usually be above 60 at night, and between 75 and 85 or warmer during the day. High humidity is good, too. Lower night temperatures for several weeks in the fall, around 55 degrees, can help flower stalks get started. If temperatures fluctuate, buds that are ready to open can drop.
Phalaenopsis doesn’t have a way to store water, so it shouldn’t be allowed to dry out completely. But they shouldn’t sit in water, either. Water thoroughly, then don’t water again until the plant is nearly dry. To keep it from rotting, water in the morning so the leaves are completely dry by nightfall. Humidity is also key, and the recommendation is between 50 and 80 percent.
American Orchid Society suggests fertilizing on a regular schedule, especially during warm weather when moth orchid is growing. If the plant is in a bark-based medium, use a high-nitrogen fertilizer (30-10-10). A high-phosphorus product (10-30-20) can promote blooming.
If you need to re-pot a moth orchid (and that should happen when the potting medium starts to decompose, or every one to three years), do the job in the spring, immediately after the orchid finishes flowering. Remove the old medium, trim soft or rotted roots, and spread the remaining roots over a handful of medium in the bottom of a new pot. Fill the rest of the pot with medium, working it in among the roots. The junction of the roots and the stem should be at the top of the medium.
One final thing about moth orchid: of the orchids commonly available, it’s the only one that will re-bloom from its old flower spike. When the last flower fades, don’t cut the spike, or cut off the stem leaving two nodes – the lines on the stem below the flowers. One of the nodes may initiate flowers within eight to 12 weeks. It might not work, but it’s worth a try.
If you really get into growing orchids, check out the regular meetings and events of the Orchid Society of Middle Tennessee. I’ve added a link to their site in the Local Garden Organizations listings in the column on the right.