Stanhopea growth cycle

[cpeters5]

I won an old stanhopea from an orchid auction this Spring. I repotted it right away, saw two very young spikes getting ready to emerge. I splitted the plant into two pieces and repotted them in chicken wire baskets lined with coconut fiber. I put both plants outside on a shaded balcony, with dabbled sunlight from morning till early afternoon. Both grew two new bulbs and plenty of roots, but no flowers. I assumed the stress from repotting killed them.

When outside temperature dipped to around 50F 4-5 weeks ago, I moved all my orchids (mostly cat, vanda and den) to a semi greenhouse environment in an all glass sunroom with a mini-fogger and ceiling fan. The relative humidity in the sunroom was kept around 70%, and night temperature was around 60F. Since then, all plants growth seemed to slow down. Most of the green root tips shrink and turned white. But I thought this is natural for them.

However, the two Stan plants bucked the trend. I saw two seemingly healthy tips emerged from each plant, they look like they could be new shoots. Is this natural for Stan? Do they grew new bulbs during Fall? And when do they produce flowers?

Thanks,
pax

[euplusia]

This is a very difficult question. There is no universal Stanhopea. Some warm growing species grow and flower year round. Other species only flower in summertime. Some species need a long dry winter rest (for example jenishiana). And some species nearly never flower in cultivation and frankly I don't know what to do.

[cpeters5]

Thanks euplusia. For waht it worth, mine are Stanhopea impressa. Judging from the spikes I saw in the original pot, which was around late spring, I suspected this plant naturally bloom during Summer.

I just want to make sure I am not doing anything to encourage them to grow when they are supposed to be resting.

If this is the case, are the new growths indicating that they are receiving too much water or light at this time? Should I stop watering them. Currently, I only mist my plants daily in the morning.

[euplusia]

Stanhopea impressa normally flowers here in May/ June. Being from altitudes between 800-2000 meters from the western Andean slopes of Ecuador, I assume that the dormancy is not very marked. I would reduce watering, but not stop completely.

[Manfred Busche]

Hi Pax.

I cultivate 250 Stanhopea plants, big and small.
May I comment as follows ...

By splitting your plant, you have encouraged her to do something about this sudden condition change,
and as a response, both plants (divisions) have started growing.

Your night temperature of 60F=16°C suggests day temperatures of about 25°C, which is quite normal for
medium- to high-altitude Stanhopea plants to entertain growth.

May I suggest that you give both plants as much light as possible, even full sunlight(!), and
that you spray on the compost a good fertiliser 30-10-10, 150 ppm, every day, during warm periods of the day.

Under this treatment, both plants might grow even more shoots - and
you might get some headache how to raise these to maturity before winter arrives in Maryland ...
When maturity has indeed been achieved, plants must be 'rested' to be able to flower in spring.

Regards and luck, Manfred .

(a) A 'good fertiliser' contains all macro and micro nutrients.
(b) 'Maturity' means a 30 cms high leaf plus a strong bulb from any or all of the shoots.

[cpeters5]

Thank you for your valuable tip. I just moved both plants to the sunniest spot in the sunroom and fed them as you suggested. 140ppm very day is quite a feast! Winter is only a short time from now. If the new shoots do not mature by then, should I continue to feed (or simply water) them into winter as long as they are still growing?

[Manfred Busche]

Under the treatment I have suggested, it is possible to raise leaf shoots of Stanhopea plants to maturity
within approx. 3 months.

It is however imperative that you maintain present temperatures (25°C / 16°C) and present light levels
in your 'sunroom' until January next year. If the sun becomes dull, you could supplement with
artificial light (tubes), see old Orchid Board thread titled 'Stanhopea platyceras bud drop' ...

To answer your question : you may feed as long as these shoots grow - and grow they will, if you are able to
provide 'Cattleya light' and decent temperatures ...

[flexdc]

I agree with Manfred. I have a Stanhopea tigrina grown outside in my garden here in Southern California. Our winter temperature approximates what you have in your sun room 50s/12-15 nights and 70s/20+ during the day. My tigrina usually starts to put out new growths in September and continues to grow till around Christmas before it stops. I continue to water and fertilize during this time, however always in the morning. Then it flowers in May.
Andrew

[cpeters5]

Andrew,
Mine grew new shoots twice this year. First time around July, when the two plants grew two shoots each. Those shoots have already matured. This is the second time, the two plants grew new shoots again in the same year 3 months apart. That's why I was wondering if they got the wrong signal from me to keep growing when they should be resting.

[flexdc]

In this case I think the more the merrier. I would still grow those to maturity before cutting down on the watering. The only rest mine gets is immediately after flowering. Do post some pics when it flowers. I bet it will be quite a show!!
Andrew