Calanthe rosea
 

I split my Calanthe rosea plant into 6 pots. What I’ve read is not to water until new growth is about 6” high or roots have grown down into the soil. One of the 6 has reached that stage and has been put outside for the summer. The other 5 are still in the greenhouse where temps go up to 95° with no way to cool it down. Right now there is a ceiling fan on. Those are the only orchids still indoors. Could it be they’re not growing (they’re all at about 2” and short roots) because of the heat? I was trying to keep them dry until they reached the “proper size”.

Any ideas? I’ve had the main plant since about 2012 but for some reason never divided it before. They look healthy!

In your climate I would put them outside, maybe under an overhang so they don't get rain. The normal day-night temperature changes might convince them to start growing.

Since it is summer, I would water them even if they are small. This is the time for them to grow, they may need a bit of encouragement. Otherwise they may just stay small to protect themselves from a "drought".

Thanks. I’ll try both.

Since my last posting on calanthe I’ve put all of them outside. Only one has grown. The rest just sat there all summer. Just this weekend I put all of my orchids back inside. Any ideas on why the 5 didn’t grow. Their leaves are about 1”-2” and hardly a root on the bulb but what there is looks good.

Just saw this thread now. What you read is not really correct.

Calanthe rosea, and the other decideous Calanthes can be grown in either spaghnum, or a terrestrial mix (I use the latter, coarse peat, composted manure, perlite and a little bark).

After blooming, you stop watering. You can take plants out of the pots if you like. Since these are greedy plants, they should be repotted annually. It is normal to divide into 2 pseudobulb divisions, one from current year and the one from the year before. Over the next year, as it produces new growths, the oldest pseudobulb will fade away.

Once you see new growths forming, it is time to pot them up again, but don't water yet. When the new growths are about 2" tall, you start watering & fertilizing again. At that point, I grow them together with my Cattleyas, so fairly bright.

Since they have a relatively short growing season, I use composted manure in the terrestrial mix + slow release fertilizer + watering with fertilizer every 2 weeks.

Ideally you would like to get them going by April, so the new growths can be done by October. Then you scale back watering a little, and should see flower spikes by Dec/Jan.

Then the cycle starts over.

Should I treat the 2” growth like the one normal bulb and fertilize now. I’ve just brought them siside. Also put them under bright light?

It sounds as if they are a bit off their normal 'schedule'. Yes, I would give them a chance to complete growing the new pseudobulbs.

Thanks!