I have two of these Lc. plants and one is planted in finer mix and the other is planted in a coarser mix.. The one planted in the coarse mix has gotten lighter and lighter in color (the other one has stayed a fairly dark green) and some of the stems are now turning reddish. Am I underwatering this one?
I can only speak from my experience...and I wouldn't think that's sunburn...unless the leaves look even more obviously burned. Those pseudobulbs that are older have already hardened...and wouldn't burn as easily as the leaves...especially the newer green growth. I've got a couple of cattleya alliance hybrids, and have wondered about their red tint, too. I've finally decided it must be their "normal." Do you know the name of the plant? And do the leaves look fine?
Scott
When my catts got sunburned last winter, they had large black areas on the leaves. Nothing happened to the pb's that I noticed.
I'm pretty sure that leaf color can be affected by the amount of light the plant is receiving as well as nutrients. Some orchids get very light colored leaves if they are in strong light, and dark green leaves if they are in low light. Are your two plants getting the same light conditions?
As to the two types of medium, the coarser one would hold less water, or dry out faster than the finer mix, so the plant in the coarse mix might need more water/fert than the other (or the same amount, but more often). Less nutrients could be making it paler green, too.
Do you fertilize? If so with what? Your plants may be low in phosphorous or it may be high sun (not likely in S.F.). If it is sun related it does not look like too much.
I water my cattleyas once a week. Every other week I use standard Miracle-Gro 3/4 tsp per gallon. Here's a picture of the other plant in the finer mix but otherwise essentially identical conditions.
dyzzy, the two plants live on the same garden window. I don't always put them back in exactly the same spot after I water (it's quite a large window) so they have been moved around a bit but always on the same window.
This message was edited Jun 14, 2012 2:02 PM
Maybe you should try using a fertilizer formulated for orchids instead of the standard Miracle Gro. Most orchids need the nitrogen in the fert to be not derived from urea because they can't utilize the urea-base nitrogen. IF what you're using is Miracle Gro for Orchids, it's fine.
I mist my orchids every day with a 1/4 strength orchid fert solution. (that's mixed at 1/4 the amount they recommend on the package) Then I dunk them all in rainwater every week both to thoroughly water them, and to wash away any accumulated salts. But mine are outdoors in a lot warmer climate than yours so you most likely don't need to either water or fertilize as often. Still, as the sun gets stronger, and temps go up your orchid will use more of both, so you should step it up as the days get longer, and then taper down again.
Also bear in mind the different mediums, as noted above.
I will definitely switch to a different fertilizer soon, I'm working on using this one up. I still have 2-1/2 bags left to go though :(
Don't bother to use standard ferts on orchids unless they are terrestrials. Dyzzy gave the reason. They are not able to efficiently take up formulations for terrestrial plants because of the mediums they grow in and their epiphytic nature. They can't use the nitrogen in urea based formulas well. Nitrogen is heavy in formulations for orchids but should come from a non-urea based formulation.
I've read that you should use urea-based ferts when using a bark medium because the bacteria need the nitrogen to be able to break down the bark.
I've never read that, Greeneyes, in fact quite the contrary. Like Laurel, I only use urea based nitrogen on terrestials.
Jim
Uh, uh! that 2 1/2 bags of Miracle Gro will last you way too long even if you're feeding a whole lot of plants. A little box of orchid-specific fert will only cost you about $3. My first package of Miracle Gro for Orchids lasted over a year. (I only had a few orchids . . . then)
I'd use the regular Miracle Gro for your other plants (or get some terrestrial orchids!) and invest the few bucks to get your orchids growing through the summer. You could miss out on blooms later in the season if they don't put up vigorous summer's growth. The bacteria that break down your bark can use any type of nitrogen. You really need to supply nitrogen that the orchids can use.
So I've been reading up a bit on this. I don't want to start an argument, but.. :)
What does everyone think of this post?? http://forums2.gardenweb.com/forums/load/orchids/msg032222191547.html
Gotta be careful what info you buy into on the internet. There's doubt in my mind that the fellow who wrote that post is any kind of expert.
He says: "Almost all published studies done on fertilizers and plant nutrients have been done on crop plants. I do think though that much of this is transferable to orchids."
Pretty sure that what he 'thinks' is wrong. Orchids, at least most of them, are epiphytes designed to absorb nutrients and moisture from the air in their native habitats. That's the reason they don't metabolize urea-based nitrogen well, if at all. Very few crop plants are epiphytes. Whole different animal, in fact it's like comparing a horse to a bird. So at the get-go his whole article is in doubt for me.
On the other hand, my favorite orchid book written by two professors from UF has a short piece on fertilizers in which the issue of urea is not mentioned once! Very surprising. My personal experience is that the non-urea fert works better, though.
Hope Laurel will find time to chime in on this.
I took three orchid classes from the curator of orchids at the USF Botanical Gardens. He says only use non-urea fertilizers on orchids. Bill Thoms, the guy who wrote the book on bulbos, makes fertilizer and sells it at our orchid club meetings. It is non-urea as well. The chap who made the post is simply wrong.
Jim
Jim, I think his logic is flawed but he may not be wrong. Where's the data on this? Have there been documented studies? Who's the authority you can really believe? Is the urea thing just a "long held belief" ?
My other source book on orchids co-written by two orchidists (one a botanist and AOS judge) with 35 and 40 years of experience respectively says:
"Generally, urea-derived nitrogen is less available and less desirable than that derived from ammoniacal sources. . . urea-based nitrogen is cheaper and more stable than ammoniacals." from 'Four Seasons of Orchids' by Greg Allikas and Ned Nash. They don't show a source for their info.
So since my curiosity is driving me on here, I sent an e-mail to Robert J. Black at the U of Florida, professor emeritus in Environmental Hort and co-author of "Orchids to Know and Grow". I'd hope that if there has been a study done on this subject, he will know about it. Will update if/when I get a response from him.
Meantime, let's see if we can get a concensus from the Orchid Forum at large. See new thread entitled "Urea vs. non-urea fertilizers" coming soon to a forum near you . .
Elaine
It is already well documented but at the end of the day it's a "to each his own" thing. This is what makes this forum chill while the one at that other place has chronic explosive arguments. From here the discussion could move to how much and how often. That's another area of hot debate. I think each person needs to grow using their own comfort level with the information that's out there. You can't say orchids are forgiving and then say there's only one way to do it.
Rather than consult us or an expert recommended here or elsewhere on line, why not go to the AOS site on orchid care and see their recommendations? They are a clearing house for reliable education. Their information involves all the orchid researchers and experts out there.
I've got a couple of little Lc's and a couple of Pots, and am getting set up to conduct my own (completely unscientific) experiment. For the rest of the summer, maybe until October or so, I'll give one of each the regular Miracle Gro, and the other my non-urea orchid fert. They'll be in the same location, and all are in the same medium and same type of pot.
At the very least, it will set my own curiosity to rest. So far, the American Orchid Society has failed to do so.
Here's the general note on fertilizer from the AOS site. http://www.aos.org/Default.aspx?id=78
But on the culture sheet for Cattleya and 9 other types that I looked at, the section on fertilizer makes no mention of non-urea formulations. On the "novice" culture sheets it does specify "orchid fertilizer". http://www.aosforum.org/education/cattleya.pdf
This message was edited Jun 15, 2012 7:58 PM
Forgot the picture of the little guinea pigs . .
I found some references. For each, I went to the AOS site, selected 'search' in the upper right, and typed 'urea.' Then, in each article found, I hit Ctrl+F (to open my browser's 'find' tool) and typed 'urea' again. It highlights every instance of that word in each article. Taken from a couple of those articles I found:
I. Capitalizing on the high-growth season: Because of the increased light and temperatures, your plants will benefit from more fertilizer (increased frequency NOT concentration). This is especially true for those varieties that put out new growth during this time. Avoid fertilizers that contain significant amounts of urea. Urea requires soil organisms to convert it to forms useable by orchids and the process liberates significant amounts of acid. If you are growing in a predominantly inorganic media like rock or aliflor, soil organisms aren't prevalent and these media have poor buffering capacity. If you are growing in fir back media, as the medium ages, it naturally becomes more acidic and less able to buffer the pH shifts caused by metabolism of urea. ~Ron McHatton, AOS Director of Education, 2009 (from: The Sumer Doldrums: How to Care for Your Orchids Suring the Wilds of Summer / AOS)
II. We now know that opimum fertilizer is directly related to water quality and that excess nitrogen is not as important as first thought since the excess nitrogen contributes to the decomposition of the potting medium. We also know now that urea nitrogen is not efficiently used by orchids and that urea-free fertilizers are a better choice. ~Ned Nash (from: Cattleya Culture - Part 2 / AOS)
As usual, I'm conflicted (probably the Gemini in me). I know that I've been growing orchids about 5 years now, and have always (until this year) used 'regular' fertilizer...the same I use on everything in my yard. THIS YEAR, I've switched for the first time to urea-free, and I have noticed a marked improvement in my plants' growth. The conflict is that I also realize that most of my orchids are just "coming-of-age," and are putting on better growth simply because of more back-bulbs and more established plants. Either way, I'll stick with the urea-free now...given the widsom above. ;o)
