The trouble with Gongora and Paphinia

[Lars Kurth]

I have tried to grow Gongora and Paphinia with varying success, but I think I may start to get the hang of it.

In summer, both species are no problem. They like moisture and humidity and light that would suit Phalaenopsis. Paphinia seems to like it best not too high in the greenhouse (about 1-1.5m's above the floor).

However in autumn and winter I have always had trouble with sudden loss of new growth to Erwinia. Virtually new growth becomes floppy and dies over night. I have 3 strong ventilators in my greenhouse. In winter the greenhouse is not actually that humid (no hydrofogger; when it is cold outside the heater dries the air). I was also wondering whether I just have a Erwinia hot-spot somewhere in the greenhouse, so I kept the plants in different corners of the greenhouse and added a bit of Physan 20 to the water once a month. Still, healthy plants have been affected.

The problem seems to be that not all new growth has properly hardened and seems to be ultra sensitive to condensation just before the pseudo-bulbs mature. Autumn seems to be most dangerous as the heating is not yet on full, the greenhouse does not get enough sun and thus plants generally stay moist for longer. In winter we don't get enough light which seems to affect the plant really badly and prevents bulbs from maturing.

What I started doing is the following: in September I move Gongora and Paphinia into the gable of the greenhouse where it is warmer, drier and brighter. I kept one plant in its original position. The plants that have been moved have not had any issues. Even plants that lost new growth before. The plant which I kept in its normal position lost two of its four new growths to Erwinia. I have bathed that plant in Physan and put it into the gable as well. In March, the plants can go back to their summer positions.

The only draw-back: if it gets too cold outside and the greenhouse heating is on all the time, it can happen that the plants get are too dry for too long. This means that winter flowering plants can drop their flower buds.

[Manfred Busche]

I grow Stanhopeinae (Gongora and Paphinia and others) in the Tropics, hence I cannot comment
on greenhouse problems that occur in the Northern Hemisphere ...

However, I know that Stanhopeinae need more fertilizer than most people are aware of.

Before you 'hang up' on Stanhopeinae, you might try to give your plants (when they are active) as much light
as experienced growers would give to a Cattleya plant, plus fertilizer 150 ppm per day / 35-10-10.
With these provisions, shoots will grow faster and stronger to be a new leaf with a completed bulb
before(!) the hard times are looming.

'Erwinia' is not the cause of the problem but the effect - it mostly befalls shoots that are on their way to demise
anyway, e.g. because they are starving ...

Dropping flower buds of Stanhopeinae :: you might fertilize the plant with 10-50-10 / 150 ppm per day,
because the plant cannot sustain the inflorescence without proper nourishment.

[isurus79]

That is some really interesting advice Manfred. I also grow all my Gongoras and Paphina very bright (Cattleya bright) and with a lot of fertilizer and they do very well, though living in Hawaii I cannot speak to the cold, wintery conditions of the UK.

[Lars Kurth]

Before you 'hang up' on Stanhopeinae, you might try to give your plants (when they are active) as much light as experienced growers would give to a Cattleya plant, plus fertilizer 150 ppm per day / 35-10-10. With these provisions, shoots will grow faster and stronger to be a new leaf with a completed bulb before(!) the hard times are looming.

Thanks for the advice. At least with Gongora, I tend to get fully grown bulbs during the summer. The problem are late-comers or a second flush of bulbs that start in late summer. The Paphinia I have are imported plants: this means it takes ages for them to get going. I have had real trouble getting them to form full bulbs before the summer is over. Maybe lots of fertilizer is the solution.

The dull UK winter weather and 8 hours of daylight in winter doesn't help. It means that I have to be extra careful in spring: plants burn really easily.

As an aside: I have no problems with Stanhopea or Sievenkingia.

[Manfred Busche]

Stanhopeinae, adult plants ::

Any 'second flush of bulbs' is undesirable because it is detrimental to the process of flowering ...

When the 1 or 2 bulb(s) of the 'first flush' are forming, please go on fertilizing. After the bulbs have reached
approx. 80 % maturity, stop fertilizing but continue with plain water.
When the bulbs have reached 100 % maturity (observe their plumpness), stop watering and let the plant rest
during the dark days, until spring - when spikes will show ...