edwmax

38°C is a bit hot for the plants and may slow growth. Your best results would be between 27°C to 32°C. ... Is the outside temp cooler than in the shade house? If so then fans can be used and possibly fine water mist (depends on humidity) to cool the inside.

I just moved my nana plants out of my greenhouse this week since night time temps are above 15°C (60°F) and I can no longer keep temps below 38°C during the day.

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louis14

Thanks for the suggestions
These are local varieties and I suppose they have to be used to these temperatures. I will open the vertical wall shading tomorow anyway to allow them to get some more breeze, just in case. Current temperature max-min are 37.4°C and 23.7°C. Current RH is in the 70% and can reach 90% if its raining.
Another factor is that these first 70 plantlets come from the experimental boxes that were basically positionned in the shade of our field shed, under a corrugated cement roof therefore. The plants are probably having to adapt to the 50% green shaded full sunshine which is basically providing more light than the plantlets received during their first couple of weeks in the boxes. New leaves need to grow, in the darker green colour to cope, I assume. I am not too worried right now as they also have to developp their root system and of course, some had more roots than others. The auxiliary buds have basically no roots at all. They have all been treated with IAA to assist with root development.
I have over a thousand pups under the same conditions in another tent and they are thriving right now.
We have built new boxes already, under the same light and temperature conditions (50% green shade, plastic HDPE roof) so I suppose the new plantlets will come out already more prepared. Interesting to note that the temperature in the new boxes is monitored 24H and reaches 45°C in the afternoon. Still OK, as according to my readings, in the C.A.R., they aim for an ideal 50°C in the box, for optimum macro-propagation.
We will be installing a water misting system in the new boxes but still need to build the frame for the solar cell as we are off the grid. Plenty to do...Not enough hands...

edwmax

I find with the banana varieties I grow, that when the air temp is 32-38°C (90°'s F) misting with water several times during the day & insuring the soil is not dry the plant grows fine. But ... when the air temp is above 38°C (100%deg;F) the leaves will fold up regardless of water. The plant goes into a self preservation mode (dormant??) to retain water. ... So I just don't see air temp over 38°C desirable for bananas nor the 50%deg;C (122%deg;F) in the propagation boxes ... Can you please post a link to the C.A.R. reference?

Just watch the banana leaves when the temps are high. Open, the plant transpiration is good. Closed & folded leaves indicates transpiration has stopped and the plant is over-heating.

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louis14

This is a link to the PDF, it is in French, and mentioning the 50 degrees C in the propagators.
Not C.A.R. actually, New Caledonia.
I find there is more complete first hand information written in French language.


https://www.google.co.th/url?sa=t&so...QpZDKJ8P86v02A

edwmax

Thanks for the link. I just learned French ......

or how to google a translation anyways.

From the 10 FAQ of your link: The first two questions.

* A quoi sert l’ombrière au dessus du germoir : Elle permet d’éviter d’avoir des températu-re trop chaudes (dépassant les 50°C). Sinon, à de telles températures, les tissus de la plan-te commenceront à mourir par brûlure ou par cuisson.

English:
What is the use of the shade above the germoir: It avoids having temperature too hot (exceeding 50 ° C). Otherwise, at such temperatures, the tissues of the plant start to die by burning or cooking.


* Pourquoi la fourchette de température 25-50°C comme objectif de température ? La technique du PIF résulte de travaux de recherche effectués en Afrique de l’Ouest sur « Bananier Plantain » par le docteur KWA (CARBAP) et qui a abouti à un mode opératoire précis qui a été reproduit avec succès par l’IAC Pocquereux en conditions locales . La four-chette 25-50°C résulte des enregistrements effectués sur le dispositif testé à Pocque-reux. Monter à 50°C dans la journée sous la cloche plastique permet de ne pas redescendre les 25 ° C la nuit et de maintenir la température dans la sciure autour de 25 °C ce qui est la température de croissance optimale du bananier

English:
Why is the temperature range 25-50 ° C as a temperature target? The PIF results from research carried out in West Africa on Plantain Banana Plant" by Dr. KWA (CARBAP) and which resulted in a modus operandi which has been successfully reproduced by IAC Pocquereux in local conditions. The fork 25-50 ° C results from the recordings made on the device tested at Pocquereux. Up to 50 ° C in the day under the plastic bell can not go down the 25 ° C at night and keep the temperature in the sawdust around 25 ° C which is the optimal growth temperature of banana

I don't see this as being any different from what I have already stated. Over 50° C temps is not good for the Banana plant or corm.While 50°C is shown as the upper range limit, you really don't want to be that high. 25°C to 38 33°C is better. Over 38°C the plant stops growing; over 50°C the plant starts dying.

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louis14

The text clearly refers to the fact that work should be done in the morning so the propagator can reach the "target" 50 degrees in the afternoon and heat up the sawdust enough so it does not go "under" (that word is missing in the text) 25 degrees at night. "Monter à 50°C dans la journée sous la cloche plastique permet de ne pas redescendre (sous) les 25 ° C la nuit".

This does not alter the fact that our Kluai Hom Tong plantlets grow out of the sawdust, into the 45 degree air of the propagator, developing 3-4 leaves and reaching 30-40cm height within a couple of weeks, looking as healthy as can be. Of course this temperature is not constant, but putting up with such a high temperature during 4-5 hours of the day does not seem to affect plantlet development in any way.
Once more, this is based on effective growing, in natural conditions, on a functioning plantation. Any need for fans, artificial cooling of any kind would be economically unsound for this simple propagation technique which is promoted to help low income farmers.
Finally, April and May are our two hottest months, things will cool down a little after that.
I'll post a progress report on our new propagation boxes in a week or so, I am waiting for them to look good.

Tytaylor77

Mine have gotten very hot in the past and it didn’t bother them. I wouldn’t recommend an exhaust or exaust fan. It could lower humidity which needs to be as high as possible.

All great ideas though!

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edwmax

In my greenhouse I use this MistyMate Twist & Mist Personal Misting System
in front of the blower. Also, these are available https://www.walmart.com/ip/Fan-Miste...ling/179856735

As well as one could make his own. The micro-misters can be obtained.
.... The mister only buys me a few weeks before I have to shut down the greenhouse due to excessive heat (120° plus).

I wasn't suggesting to ventilate the propagation boxes. That's another issue as there is no way I would allow the temperature inside those boxes to be 122°F (50°C). The thermodynamics does not work that way as implied by the referenced guide. The guide clearly states in a couple of places that 25°C (77°F) is the optimum working temperature.

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benzion72

Thanks TY for sharing. Please do you have any reference on Macro propagation, the last time i tried it, I had problem with rooting, the root are not just forthcoming

louis14

Just under two months since we placed twenty corms in each of the first two experimental boxes and we have now retrieved a total of 150 plantlets with another fifty still in there, too small to separate. The plantlets are cut away from the corm, including the roots or the closest root cluster of root even if this includes a chunk of corm. If there aren't any roots, I include a chunk of corm. The roots and lower stems are then soaked in water containing rooting hormone at the appropriate concentration. The plantlets are then replanted in sawdust for another couple of weeks to let then developp more roots. I have seen some grow a three inch long root overnight. I give them a lot of water at this time, keeping the sawdust nice and damp and they are doing well. The heat is intense and I do not cover them and they are kept in the shade of course.

Akula

Is the original corn used up at this point and requires replacement with a fresh one or does it just keep producing?

Thanks! Really cool!

louis14

The original corms are still producing. I have not added any new corms to these two boxes. Some of the corms are now just bits as the apical meristem kept producing and I had enough and retrieved the shoot with some corm by chopping the corm into two or more pieces. Never mind, the bits that are left, as long as there is a visible bud will still produce.
Next week, once the last fifty or so plantlets have been retrieved, I will empty the boxes out. It's important to properly kill the apical bud.

benzion72

Great job I learnt somewhere you can produce up to 100 plantlets from one corm. Can you kindly show the picture of how you are cutting the plantlet from the corm and the size of corm to be cut with the plantlet. Thanks

louis14

These photos of detached plantlets are further up the thread

benzion72

Did you try reactivation of any strong plantlet as advised by some literature

louis14

We did not, we look for rapid results, big plantlets quickly and we are not short of corms.

Tytaylor77

Amazing job Louis! I see some mushrooms hahhaa! I checked mine one morning and they were everywhere! In every box! Hahaha. All of my stuff is sterile like yours is I’m sure. I guess the spores just blow in when the top is off. It’s pretty amazing! Lol

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sddarkman619

Louis and Ty, are either of you using any nutrients/fertilizer for growth aside from rooting hormones? any nitrogen added or anything? and at what point?

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louis14

Once the boxes are in a producing cycle, that is after the first month or so. We give them folear feeding spray of NPK 20-20-20 every fifteen days including a dose of MgSO4 and a cocktail of trace elements and calcium (liquid form). They do fine with that.

benzion72

Do they picked up after you observation of not looking well as they were before