# Water temp??



## Carper (Dec 29, 2015)

Hi all,

I've been trying to research this question but appreciate any views as to the effects this would have on growing various types of orchids. 

My collection are mainly multifloral paphs. I use ro water and let the water acclimatise to the greenhouse temp for a few days. However, during winter the water that I am using feels fairly cool. It measures approx. 17C. 

The simple questions are;

- Is there an optimum temp for the water that would enable maximum nutrient uptake by the orchid?
- I have been growing a good number of seedlings on a heatmat with vg success & thought water temp would help with the remaining orchids in the greenhouse.

Looking forward to your replies.

Gary
UK


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## gonewild (Dec 29, 2015)

The best temperature for the water is whatever the leaf temperature is.
The easiest way to come close is to have it be room temperature.
For nutrient uptake warmer is better than colder.


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## consettbay2003 (Dec 29, 2015)

I use an aquarium heater to keep my water at 72F


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## Carper (Dec 29, 2015)

gonewild said:


> The best temperature for the water is whatever the leaf temperature is.
> The easiest way to come close is to have it be room temperature.
> For nutrient uptake warmer is better than colder.



My daytime temp is approx. 20c so would this be the best temp or a little higher. If the plants uptake nutrients better at higher temps, but in the middle of winter, ie short days/low light, would this cause any problems for the plant. I only supplement lighting on the seedlings etc.

Gary


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## Linus_Cello (Dec 29, 2015)

consettbay2003 said:


> I use an aquarium heater to keep my water at 72F



Same here. My tanks are about 78 or 82 (warmer for discus; Terry Root at a lecture said that he thought the nutrient slime from discus helped his slippers grow better).


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## phraggy (Dec 29, 2015)

I make a fresh mix whenever i water my multiflorals and I won't do it unless the water is warm to the touch. They have strong extra light for 12 hours per day and are showing extra growths on most of them. Repotted a few which are showing new root growth so hopefully I will get some of them in spike early spring.
Never heard the one regarding Discus water slime. I have none now but have bred literally thousands in my tropical years but only raised a number to adulthood -- I can understand that the water will be fine, for the slime is a nutrition for the babies,

Ed


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## Ray (Dec 29, 2015)

I, too, heat my RO tank. I shoot for 75F.

Water in an open tank will never equilibrate with the sir temperature, due to evaporative cooling.


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## gonewild (Dec 29, 2015)

Carper said:


> My daytime temp is approx. 20c so would this be the best temp or a little higher. If the plants uptake nutrients better at higher temps, but in the middle of winter, ie short days/low light, would this cause any problems for the plant. I only supplement lighting on the seedlings etc.
> 
> Gary



I would go a little higher. But not much more tan a few degrees. I dont think warmer water temperature will cause the plant to uptake minerals faster what it can do is make the uptake more efficient. Leaf temperature and light intensity and root temperature will be the determining factors.

The idea of matching the water temperature to leaf temperature is to avoid cell shock which could cause a delay or shutdown of photosynthesis.


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## gonewild (Dec 29, 2015)

Ray said:


> I, too, heat my RO tank. I shoot for 75F.
> 
> Water in an open tank will never equilibrate with the sir temperature, due to evaporative cooling.



And leaf temperature will almost always be warmer than air temperature when light is being absorbed.


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## naoki (Dec 29, 2015)

A couple of related thought (not directly addressing the question, but interesting to think about) is the optimum root vs leaf temperature. In many plants, it's been shown that the optimum root temperature is much lower than the leaf temperature. This is related to the reason why diurnal fluctaion in temperature could be beneficial. Both photosynthesis and respiration increases with temperature (within the reasonable range), but the pattern of increase is different (PS rate saturate, but respiration keep increasing). Plants want to maximize the (photosynthesis rate) - (respiration rate) to grow. See Fig 3 of http://www.ext.colostate.edu/mg/gardennotes/141.html

So for non photosynthetic roots (or plants at night) want to have lower temperature to minimize energy loss due to respiration.

Lance, leaf temperature is not necessarily higher than air temperature. Due to the transpiration, leaf temperature could become lower in some situations. Plants do actively control the temperature via stomata control (some people say that plants are limited homeotherms) (related info). While I was learning about Arduino, I saw some indoor growers use the leaf temperature (e.g. with IR sensor) to guide the amount of artificial light (it would be cool to automate this with Arduino).


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## gonewild (Dec 29, 2015)

naoki said:


> Lance, leaf temperature is not necessarily higher than air temperature. Due to the transpiration, leaf temperature could become lower in some situations. Plants do actively control the temperature via stomata control (some people say that plants are limited homeotherms) (related info). While I was learning about Arduino, I saw some indoor growers use the leaf temperature (e.g. with IR sensor) to guide the amount of artificial light (it would be cool to automate this with Arduino).




Sure leaf temps can under certain conditions become lower than air temps. But under normal orchid growing conditions indoors under lights or in greenhouse under sun they are generally higher than air temp. :wink:


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## abax (Dec 30, 2015)

I keep the water heater in my greenhouse set on 70F all
year round. My rainwater for Phrags. is normally a few
degrees lower at about 65F. I've been varying the temps.
for Phrags. and Paphs., Phals. for about a year and find
the plants seem to be quite happy with it.


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## Stone (Dec 30, 2015)

In winter (when it's about 8 to 10C outside), 20C water will almost feel hot - certainly warm. On a hot day in summer (like today-about 90C outside), 20C feels cold. Don't go by what the water feels like to mammalian nerves. IMO 20C is a perfect water temp for tropical plants all year.


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## Carper (Dec 30, 2015)

Thanks for all your comments of which I will be applying in my new year trials. I always like to experiment and bring in new ideas for the new year. After a bit more general reading can I also have your views on these 2 please. I normally feed 13-3-15 @ around 400 u/S in RO water. Supplement maxicrop seaweed extract, epsom salts occasionally. PH is around 5.9.

- I was thinking of an application of mono ammonium phosphate.12-61-0. How often would you apply and at what strength. On its own or add to a feed.
- Came across this article and thought it was a joke! What is the advantage and has anyone ever tried it? The addition of alcohol!!!!!

http://www.staugorchidsociety.org/PDF/OrchidWANTSbyWeymanBussey.pdf

Gary
UK


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## gonewild (Dec 30, 2015)

Stone said:


> On a hot day in summer (like today-about 90C outside), .



Where do you live anyway? Hell?


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## gonewild (Dec 30, 2015)

Carper said:


> - I was thinking of an application of mono ammonium phosphate.12-61-0. How often would you apply and at what strength. On its own or add to a feed.



What is the purpose?


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## consettbay2003 (Dec 30, 2015)

Carper said:


> Thanks for all your comments of which I will be applying in my new year trials. I always like to experiment and bring in new ideas for the new year. After a bit more general reading can I also have your views on these 2 please. I normally feed 13-3-15 @ around 400 u/S in RO water. Supplement maxicrop seaweed extract, epsom salts occasionally. PH is around 5.9.
> 
> - I was thinking of an application of mono ammonium phosphate.12-61-0. How often would you apply and at what strength. On its own or add to a feed.
> - Came across this article and thought it was a joke! What is the advantage and has anyone ever tried it? The addition of alcohol!!!!!
> ...



What is the source of nitrogen in your 13 -3-15?


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## Ozpaph (Dec 30, 2015)

gonewild said:


> Where do you live anyway? Hell?



But its heaven when its low 80s! (for weeks on end, at least up in Brisbane).

My orchids get ground temp water 365/7. In winter that's probably in the low 60sF; though heated glasshouses are uncommon in this part of the world.


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## gonewild (Dec 30, 2015)

Ozpaph said:


> But its heaven when its low 80s! (for weeks on end, at least up in Brisbane).



90c ?.
I'm assuming it does not reach 90c on the surface even in Australia. oke:


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## Carper (Dec 30, 2015)

gonewild said:


> What is the purpose?



Lance,

Just reading through various comments and threads that some growers get better growth through urea based nitrogen. Thought that feeding alternately might be worth a go. 

Live in Nottingham in the UK. Getting milder, wetter, fair winters but poor summers!!! We're in the middle of winter, had no snow yet, don't think a frost, and temps outside have been 15-17C. Still very short days, just lengthening form about 7 hrs of very poor light for the next 3-4 months. 

Gary


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## Carper (Dec 30, 2015)

consettbay2003 said:


> What is the source of nitrogen in your 13 -3-15?



Here's the link to my feed;

http://www.akerne-orchids.com/shop/index.php?route=product/category&path=40

Gary


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## consettbay2003 (Dec 30, 2015)

I also use Akernes but I supplement it with either urea or ammonium sulphate. I use orchiata bark and they recommend that the fertilizer
should have more ammonium than nitrate nitrogen.


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## Linus_Cello (Dec 30, 2015)

Carper said:


> Thanks for all your comments of which I will be applying in my new year trials. I always like to experiment and bring in new ideas for the new year. After a bit more general reading can I also have your views on these 2 please. I normally feed 13-3-15 @ around 400 u/S in RO water. Supplement maxicrop seaweed extract, epsom salts occasionally. PH is around 5.9.
> 
> - I was thinking of an application of mono ammonium phosphate.12-61-0. How often would you apply and at what strength. On its own or add to a feed.
> - Came across this article and thought it was a joke! What is the advantage and has anyone ever tried it? The addition of alcohol!!!!!
> ...



I've never tried it, but a speaker on cattleya's recommended an occassional small dosage (don't remember if rubbing alcohol or vodka) when watering (like a cocktail). It makes sense in that some nutrients are more alcohol soluble (not water soluble) allowing increased uptake to the plants.

I've also seen rubbing alcohol use as a flower stem inhibitor for really tall paperwhite narcissus.


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## Ray (Dec 30, 2015)

That Bussey document is riddled with opinions (shall I say assumptions?) stated as fact, so read that with a mouthful of salt...

There is nothing in our water soluble fertilizer formulations that is more soluble with an alcohol addition.

Yes, isopropyl alcohol can be an adjuvant (surface tension reducer), but surface tension is not a significant factor in root uptake, like it would be in foliar absorption. A drop or two of Dawn detergent will be more effective if you have such a need.

Ethanol was shown to be an effective growth accelerator in plants, but only those that grow in high-light conditions. I had a long series of discussions with Brian Monk (DVM, blue llama orchids) on that, and he speculated that the alcohol acts as a ready source of extra carbon, which might be the rate-limiting factor otherwise - just as runners' speeds are limited by the body's ability to pump oxygen to the muscles.


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## Carper (Dec 30, 2015)

consettbay2003 said:


> I also use Akernes but I supplement it with either urea or ammonium sulphate. I use orchiata bark and they recommend that the fertilizer
> should have more ammonium than nitrate nitrogen.



At what rate/frequency do you apply ammonium sulphate and do you apply on it's own?

Gary


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## gonewild (Dec 30, 2015)

Carper said:


> At what rate/frequency do you apply ammonium sulphate and do you apply on it's own?
> 
> Gary



You would be using the ammonium sulfate to increase the ammonium nitrogen in the fertilizer so to be of any real value you need to mix it with the other fertilizer solution as a constant feed.


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## consettbay2003 (Dec 30, 2015)

Carper said:


> At what rate/frequency do you apply ammonium sulphate and do you apply on it's own?
> 
> Gary



What amount of Akernes are you adding to a gallon of RO water?


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## Carper (Dec 30, 2015)

consettbay2003 said:


> What amount of Akernes are you adding to a gallon of RO water?



Slightly less than the recommended amount, approx. 1.85 gms per UK gallon (4.54 litres = gallon). They recommend 1/2 gm per litre. I have found within my conditions that I get good growth around 400 u/S. However, I feel this could be better. I started to experiment with Dyna Gro bloom with plants coming into spike and found they had a higher number, better flower production. 

Gary


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## consettbay2003 (Dec 30, 2015)

I would need to know the amount of fertilizer in tsps. to be able to do the calculation.


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## Carper (Dec 30, 2015)

consettbay2003 said:


> I would need to know the amount of fertilizer in tsps. to be able to do the calculation.



It's about 1/3 of a tspn per gallon of ro.


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## Ozpaph (Dec 30, 2015)

gonewild said:


> 90c ?.
> I'm assuming it does not reach 90c on the surface even in Australia. oke:



I try to 'speak' in a language our no SI unit readers (ie USA) can understand.....oke:


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## Carper (Dec 30, 2015)

I'll begin with this then on a few plants for a few months to see if there are differences to my present feeding programme. I have a few identical plants so this would be a good place to start. Have you tried this formula on your plants?

Thanks for the advice.

Gary


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## gonewild (Dec 30, 2015)

In a UK gallon you now use 1.85g of 13-3-15 
(assuming all N is nitrate)

(all numbers are approximate)

If you mix 1g of 13-3-15 and 0.5g ammonium sulfate per UK gallon you will be applying a fertilizer ratio of 13.5-2-10 at approximately the same strength as you have been using. 

The difference is 45% of N will be from ammonia.
You would be applying slightly more nitrogen and slightly less phosphorous and potassium.

But that sort of goes an opposite direction from your idea about using mono ammonium phosphate.


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## consettbay2003 (Dec 30, 2015)

ammonium phosphate is very unstable.


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## gonewild (Dec 30, 2015)

consettbay2003 said:


> ammonium phosphate is very unstable.



Opps, it should have read mono ammonium phosphate.


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## Carper (Dec 30, 2015)

gonewild said:


> In a UK gallon you now use 1.85g of 13-3-15
> (assuming all N is nitrate)
> 
> (all numbers are approximate)
> ...



Substituting 45% of nitrate nitrogen with urea nitrogen is surely a good place to start the experiment, being most of the other nutrients are very similar. There could be a significant improvement in the plants or are there some negatives that could occur?

Gary


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## gonewild (Dec 30, 2015)

Carper said:


> Substituting 45% of nitrate nitrogen with urea nitrogen is surely a good place to start the experiment, being most of the other nutrients are very similar. There could be a significant improvement in the plants or are there some negatives that could occur?
> 
> Gary



The pH may drop lower. That may be good or bad.
There can always be negatives that occur but that is why you want to experiment, to see what works best in your environment.

The best ratio of nitrate/ammonia nitrogen will forever be an ongoing argument. I vary the ratio frequently and can see the difference in plant response but in all honesty I can't say one way is better than the other. In grow under natural light with very variable temperatures and as conditions vary so do my nutrients. If you grow under lights and conditions are very consistent then you can probably settle on one specific nutrient formula.

Experiment based on your best guess.


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## Carper (Dec 30, 2015)

gonewild said:


> The pH may drop lower. That may be good or bad.
> There can always be negatives that occur but that is why you want to experiment, to see what works best in your environment.
> 
> The best ratio of nitrate/ammonia nitrogen will forever be an ongoing argument. I vary the ratio frequently and can see the difference in plant response but in all honesty I can't say one way is better than the other. In grow under natural light with very variable temperatures and as conditions vary so do my nutrients. If you grow under lights and conditions are very consistent then you can probably settle on one specific nutrient formula.
> ...



I grow only a few seedlings under the lights and on a heat mat which are working very well. My other plants are based around the UK seasons which aren't great. However, I run temps of around 15c min/20c through winter, and the only thing I adjust is feed strength. It can drop as low as 200 u/S in winter due to low light levels/plants not being able to photosynthesize to 650u/S in summer. Higher feed strengths caused me problems in the past. I have over the past few months adjusted my PH from around 6.3 to 5.9 at every watering and found the plants have reacted to better growth, possible uptaking nutrients more efficiently. 

Lets hope my new experiments bring positive results.

Gary


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## gonewild (Dec 30, 2015)

Carper said:


> I have over the past few months adjusted my PH from around 6.3 to 5.9 at every watering and found the plants have reacted to better growth, possible uptaking nutrients more efficiently.
> 
> Lets hope my new experiments bring positive results.
> 
> Gary




The addition of ammonia nitrogen may make the pH adjustment for you.

I'd probably stay with the standard fertilizer mix when conditions are cold and use the added ammonia when it is warm.


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## Stone (Dec 30, 2015)

gonewild said:


> Where do you live anyway? Hell?



I was lying in bed last night and it just popped into my head that I should've written ''F'' not C. Then I thought to myself ''I wonder who will pick up on that?''. Then I thought ''I bet Lance does'' :rollhappy:


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## Stone (Dec 30, 2015)

gonewild said:


> The addition of ammonia nitrogen may make the pH adjustment for you.
> 
> I'd probably stay with the standard fertilizer mix when conditions are cold and use the added ammonia when it is warm.



Agreed. You should restrict your Urea/ammonium use in winter. Or better still not feed anything unless you have lights and temps above say 23C during the day.


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## gonewild (Dec 30, 2015)

Stone said:


> I was lying in bed last night and it just popped into my head that I should've written ''F'' not C. Then I thought to myself ''I wonder who will pick up on that?''. Then I thought ''I bet Lance does'' :rollhappy:



:noangel:


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## abax (Dec 30, 2015)

Just as an aside, might it much easier and better for the
plants to add additional light during overcast weather. Home constructed LED light fixtures are rather inexpensive
and really make a difference in growth and blooming during the winter months. I might add that more light
won't hurt your plants.


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## abax (Dec 30, 2015)

Stone, I caught it too, but thought you might be heat
crazed. Better not to mention mental deterioration in
public. ;>)


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## gonewild (Dec 31, 2015)

abax said:


> Stone, I caught it too, but thought you might be heat
> crazed. Better not to mention mental deterioration in
> public. ;>)



Isn't that already public knowledge?
:wink:


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## Carper (Dec 31, 2015)

abax said:


> Just as an aside, might it much easier and better for the
> plants to add additional light during overcast weather. Home constructed LED light fixtures are rather inexpensive
> and really make a difference in growth and blooming during the winter months. I might add that more light
> won't hurt your plants.



I only have supplemental lighting on a small area at present which is used for seedlings on a heat mat. I may consider doing the whole greenhouse at a later date.

Gary


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