Quote:
Originally Posted by spetrizio
I have my orchids in GH with RH 70-75%, also with good air movement.
my temperature range is much wider. during the winter min night temp is 59-60, and day temp vary on outside conditions, on sunny weather 75-77 on cloudy 69-70.
during the summer night temp is 67 or higher if outside temp is higher, day temp between 80-95.
I thnk dry sheath is not so big problem. do not cut it, maybe something will start to grow. maybe it just need time.
bigger problem is bud blasting.
some possible reasons:
- fungal infection
- not good conditions at right time - too high/low humidity/air movement/temp/light
- plant shifting during bud development
- some hormonal disbalans
- genetic - some orchids are more affected especially hibrids of monofoliate types
- calcium/magnezium deficiency
for me it seems that you are watering too frequent. 3 days in terarium with RH 75%!?! my cattleyas are in clay pots with side holes, with large bark, strong air movement, and needs 7 or more days to be completely dry.
also try do decrease night temp, to increase light if it is not sufficient, to apply fungicide if you think that problem could be with fungi
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Thanks for your culture info. I'm particularly interested in the issue with shifting the plant during develolment of the sheath. I have most defintely placed the plant in different orientatons to my light. I grow exclusively indoors, under a combination of different lights. This one is under a Metal Halide light.
The plants definitely dry out between waterings, they feel very light and the roots are all solid white. When I've repotted in the past, I have not seen any sign of excessive moisture in the middle, the roots grow all through the media quite happily and I've never had root rot. They are in clear plastic pots that I have modified by adding alot of ventilation slots - it's pretty close to a kind of net pot; I use a mix of 60/40 Orchiata bark and charcoal. Perhaps a bit excessive in terms of ventilation and speed of drying, but when I first started with orchids 1.5 years ago, I had nothing but problems with plants in moss amd have had pretty good luck so far with the bark and charcoal. Except for this darn plant!
Taking your info above into account, I am going to make sure I do not shift the plants when I return them to their tanks after watering. There are two new sheaths growing now, so it would be nice to finally see and smell these flowers.
I also wonder about a possible Ca/Mg deficiency. I had used RO water and the MSU for RO fertilizer at a rate of 1/4 teaspoon per gallon and they got that once a week by soaking in a pot for a bit. It wasn't until recently that I learned about the problem of getting a uniform mix of nutrients when mixing such a small amount of a non-homogenous dry powder into a gallon of water. So I have started to use a stock tank and add the fert proportionally as needed in the hopes of getting a uniform mix from batch to batch
Once again, thanks for the tips, they were very helpful.
I hope mine will bloom this year.
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