C. dowiana culture: how dry is dry - Orchid Board

coirchlid · #1 10-22-2012, 06:20 PM

I am on my third attempt raising this species. Many online sources mention that this Cattleya in particular needs to be dry during the non-growing season. During my 7 years of growing orchids I have yet to figure out what this means. My current knowledge suggests that this means that the potting medium and plant surfaces need to be completely dry before watering the orchid. Am I correct in thinking this? So if the plant is growing in a quickly drying medium (like fresh fir bark or mounted) then the plant can still be water quite frequently (let's say every other day with RH between 45 and 74%), right? Right now I'm afraid to water my dry-season-loving orchids too much but I seem to have also lost many orchids because of water deprivation while trying to keep them 'dry'.

So basically my question to growers of this species is:
What watering schedule has worked for you (considering growing seasons and other factors like medium and RH)?

I should note that I have succefully been growing Den. aggregatum and anosmum for a few years and it seems that Cattleya species don't like it that dry in their dormant period, any discussion will be appreciated. Thanks.

isurus79 · #2 10-23-2012, 02:12 PM

What are you min and max temps? What part of the country do you live in? How bright is the sun? How old is the dowiana (ie. pot size)? Finally, how old is the bark being used in the pot?

coirchlid · #3 10-23-2012, 04:12 PM

Hi Steve,

You've mention previously living in Hawaii so you may be familiar with growing conditions here (excellent blooms btw of the dowiana you posted in my other thread - thanks for sharing the pics and advice).

I'm on the drier side of O'ahu at about 200ft elevation (Royal Kunia) I have not measured light levels but my plant currently sits under translucent plastic that gets sun from about 11am to 4pm. It originally came in a 2" pot from H&R last october. I dropped the pot into a shallow 6" clay pot filled mostly with gravel and topped with a thin layer of Schultz orchid mix (some of the gravel is still visible). The Schultz mix (mostly bark) has been in storage for a few years but has been in use for about 7 month. As far as temperatures go, all I know is that winter nights often get as low as 60f and summer days are often about 85 with a difference of about 15f for day and night.

It becomes quite obvious (I think) when the plant is dry and this seems to take a day or two. My main question is: how long do I keep it dry?

Bud · #4 10-23-2012, 04:25 PM

you are right ....there are some Cattleya that needs winter rest....I am a windowsill grower and I water once a week in summer and every other week in winter from December 15 to February 15(I also hold the fertilizer) then if the plant gives me new leads then I resume the summer regimen and weekly weakly fertilizer....Hawaii do not have four seasons; you dont have frost....you can grow Cattleyas outdoors so my watering regimen might not apply to you....you have to follow the original tropical monsoon season and dry hot season of Cattleya's endemic environment
Maybe Baker's culture might apply to you

isurus79 · #5 10-23-2012, 07:21 PM

Quote:

Originally Posted by coirchlid

Hi Steve,

You've mention previously living in Hawaii so you may be familiar with growing conditions here (excellent blooms btw of the dowiana you posted in my other thread - thanks for sharing the pics and advice).

I'm on the drier side of O'ahu at about 200ft elevation (Royal Kunia) I have not measured light levels but my plant currently sits under translucent plastic that gets sun from about 11am to 4pm. It originally came in a 2" pot from H&R last october. I dropped the pot into a shallow 6" clay pot filled mostly with gravel and topped with a thin layer of Schultz orchid mix (some of the gravel is still visible). The Schultz mix (mostly bark) has been in storage for a few years but has been in use for about 7 month. As far as temperatures go, all I know is that winter nights often get as low as 60f and summer days are often about 85 with a difference of about 15f for day and night.

It becomes quite obvious (I think) when the plant is dry and this seems to take a day or two. My main question is: how long do I keep it dry?

Oh! Well then I'll just tell you how I grew my 2" dowiana to blooming size when I got it from H&R!! lol I was growing everything outside at about 500' in the Pacific Heights area, just off the Pali.

My dowiana got watered every day, year round until it got larger. In Hawaii, I was pushing all my Catt seedlings to grow year round and they did. Maybe hold off a bit when its cold and rainy in February/March, but other than that let the water flow. I also grew my plants with a lot of exposure to sun and rain, so they dried out fairly quickly. When the dowiana outgrew its 2" pot, I put it in a basket with nothing but large grade bark and it got the same treatment. Water every day, a bit less in cold/rainy times and tons of sun and wind. Oh, and don't fertilize unless the plant is in active growth.

I have to say though, I think putting your plant in a 6" pot is over-potting. Throw it in a 4" basket with large bark, maybe a bit of coir (because its dryer where you are) and hang it.

Catwalker808 might jump in and have some advice too if he sees this thread. You'll probably bump into him the next you go down to H&R.

coirchlid · #6 10-24-2012, 05:48 AM

Thanks Bud and Steve your sharing of your experiences is much appreciated.

Also (if anyone is still following this thread), I just noticed that my plant is an aurea. Is there any difference in culture between aurea and rosita? I would assume not, but I have heard of situations where different varieties of the same species have different cultural needs (eg. highland and lowland varieties of C. maxima).

Ray · #7 10-24-2012, 09:01 AM

Based upon what has been proven in S/H culture of plants needing a "dry rest period", and considering the climates such plants come from, I have surmised the following:

The necessity of a "rest period" is NOT a lack of water, it is the need for NO NUTRIENTS, particularly nitrogen.

In nature, nutrition is only provided when rain washes it down from the canopy to the epiphytes via what is called "trunk flow". If you are in a "dry season", that flow basically ceases, and older interpretations connected the blooming to lack of moisture, not lack of nutrients that can stimulate growth, which seems far more likely.

tucker85 · #8 10-24-2012, 09:27 AM

Last year Dr. Ruben P. Sauleda, owner of Ruben in Orchids, gave a presentation to our orchid society. He mentioned that C. dowiana was one orchid that he was unable to grow successfully until he saw it in the wild. He said he hadn't realized that dowiana is a rain forest orchid and requires more moisture than a typical cattleya. Here's his web-site if you want to contact him. He's has a PhD in orchid taxonomy and usually doesn't mind answering questions about growing species.

Ruben In Orchids

isurus79 · #9 10-24-2012, 11:40 AM

Quote:

Originally Posted by coirchlid

Thanks Bud and Steve your sharing of your experiences is much appreciated.

Also (if anyone is still following this thread), I just noticed that my plant is an aurea. Is there any difference in culture between aurea and rosita? I would assume not, but I have heard of situations where different varieties of the same species have different cultural needs (eg. highland and lowland varieties of C. maxima).

I'm not 100% sure of this, but I believe aurea is from Colombia and rosita is from farther north, like Costa Rica. I could be wrong and I'm definitely not sure if there is an associated cultural difference between the two. I've never heard of one though.

Oscarman · #10 10-28-2012, 02:51 AM

This has been a challenging species for me as well. Success has come from several factors:
1.) I am growing S/H and water whenever the 1" reservoir gets low. Some of my dowiana get water every day, but with the airiness of Leca there has been no problem with root rot.
2.) The plants grow fairly warm. 82-87° F day and at least a 10-15° drop in the night. 50-60% RH.
3.) I have read that they need lower light levels that other catts, but mine grow in just as bright light as other catts....maybe 16" below a 1000W MH bulb on a track.

I have not really noticed a rest period. The latest bloomer finished flowering and now has a 4" new growth.

The dowiana's from H&R are wonderful!