Orchid Care - Orchid Board

Leisurely · #1 11-12-2008, 10:48 PM

Something I stumbled upon while surfing. It is an excerpt from The Santa Barbara Society Newsletter.

"Our own Bryce Augustine spoke to the society about Orchid Physiology. Augustine graduated from UCSB with a BA in botany and currently is the owner of Monsoon Flora Orchid Lab, which he has run since 1991. He is also an AOS judge."

"As for fertilizer, Augustine uses 20-20-20 during orchid growing periods. He prefers Urea based nitrogen because its availability to plants is related to temperature. At warmer temperatures, when plants are actively growing, Urea based nitrogen is also readily accessible."

Anyone interested in reading the article use this link
http://www.orchidsb.net/resources/2006_06.pdf.

This is not the first time that I have read about Urea being recommended.

blackorchid · #2 11-13-2008, 10:12 AM

I believe that the medium has to be some what moist so that bacteria can grow and start breaking down urea into nutrients that plants can use. That's not always the case though because some orchids hate constant moisture at their roots. That's also the reason why urea are preferred for plants potted in soil.

Cym Ladye · #3 11-14-2008, 01:17 PM

Black Orchid,

I know of no orchids that prefer to be planted in SOIL.

Please enlighten me...and please do not say Cymbidiums.

CL

Uechi · #4 11-14-2008, 03:46 PM

Depends on your definition of soil. In any event, Terrestrial Orchids which includes and yes most Cymbidiums and Phaius, Spathoglottis etcetera. They grow in soil. In the wild they don't have the luxury of perlite, charcoal, the right size pine chips and potting soil. Non Urea forms of Nitrogen are readily and easily available to orchids in many cases Urea is not. The best way to use Urea is in a long term time released supplement like Dynamite.

orchids3 · #5 11-14-2008, 08:12 PM

I know there are some who use Urea as a Nitrogen source and have read articles which put forth favorable test results. As for me I dont use it. Orchid can only take up two nitrogen sources Nitrates and ammonium. Ureas is only used after bacteria break it down into ammonia. The breakdown time depends on both temperature and moisture. The problem with potted plants is that the urea washes out, if we water our plants properly especially cymbidiums which like to be damp all the time. Also the bacteria which develops to break down the urea seems to damage roots as well (my opinion). At best I think the best availability of ammonia to the plant would be at the highest temperature. Why not use a Nitrate source which is available as soon as its applied - just reduce or increase the concentration as temperature and sunlight increase?
As far as cymbidiums and soil - all I can say is "not mine". They grow in forest litter rotten logs and such in nature as I understand it - not dirt.

Ross · #6 11-14-2008, 08:18 PM

I still think this is "old school" thinking (and believe me, since I have been growing orchids since 1960s, I qualify as old school.) I think the science suggests a slow but steady supply of weak nitorogen (125-150ppm) with every watering. This binge then starve strategy was typical back in my old days (and I did this as well) but after following the pattern suggested by MSU tests and Ray's free info First Rays' Free Info my successes have been very good. I no longer worry about nitrite vs nitrate, I no longer worry about high nitrogen vs hi something else. It's been reall convenient for me and really successful. Check my gallery and see for yourself.

Uechi · #7 11-14-2008, 08:50 PM

Dirt versus soil interesting, as I said the defintion of soil is nebulous. The plants I mentioned are by enlarge terrestrials not aquatic, not epiphytic, not lithophytic not saprophytic. Call soil what you want they grow directly in the ground. Absolutely correct, Urea is not a good source of Nitrogen in the short term for Orchids.

Leisurely · #8 11-14-2008, 10:01 PM

I agree with what Ross has said. I began using MSU about two years ago and my orchids are doing so well but I still keep wondering when something bad is going to happen. At one time I had so many problems that I think I became a littla paranoid and I don't know how to accept everything going so well.

At the same time that I started using MSU I also began paying close attention to PH and adjusted my watering and fertilizing regimen accordingly. I always strive for a Ph between 5.5 and 6.2. Something has paid off and it is either the MSU or the correct Ph or perhaps a combination of both. There is something else that I started doing at about the same time and that was the use of a product called HB101. It is very expensive but I am afraid that if I quit using it, it will show. The only thing that I know about it is that it is an extract from certain juniper and pine and it is supposed to better enable the plant to use nitrogen.

blackorchid · #9 11-14-2008, 11:53 PM

Quote:

Originally Posted by Cym Ladye

Black Orchid,

I know of no orchids that prefer to be planted in SOIL.

Please enlighten me...and please do not say Cymbidiums.

CL

Exactly, that's not always the case with orchids, that's the reason why most commonly grown orchid will not benefit a great deal from urea. Sorry if I cause misunderstanding, English is my second language.

blackorchid · #10 11-14-2008, 11:58 PM

One thing though, if a medium is moist for most of the time and rich in organic matter and microorganism, yet still airy like those for semi-terrestial orchids like Paph and Cym, I hypothesize that urea will help the plant in a long run. Of course if you want to control the amount of fertilizer and you want it to be avalable to your plants quickly then urea is not the one that you should look at. On the plus side, urea is more "organic" I guess? (pun intended)