Why are the leaves looking yellow?
 

This is the cold season here in Northern Thailand, the night temperature has fallen to around seven degrees Celsius and damp. I find that my Leb Mue nam and Gros Michel pseudostem leaves are rather yellow as you can see in the photos I took today. These new plants have been in the ground for eight months and have started flowering in some cases. Our sandy soil is pretty dry right now, we have been watering regularly but not overdoing it. The plants were fertilized with 15-15-15 and complements during the rainy season and they thrived. We are one month into the dry winter season. Are we doing anything wrong? Many thanks for any advice.

Re: Why are the leaves looking yellow?
 

they got cold. you will lose the leaves but the plants should be ok.

Re: Why are the leaves looking yellow?
 

Thanks, should we give them extra Nitrogen then, to help with leaf regeneration?

Re: Why are the leaves looking yellow?
 

In my opinion 44.6 degrees Fahrenheit at night should not cause that problem. I think it’s something else.

Re: Why are the leaves looking yellow?
 

What 'compliments' are you giving the plants? What is the soil Ph? ... This could be sulfur, iron, & magnesium deficiency. This may be due to a 'soil lockup' or irrigation water leching the minors away.

Try a test of foliar spray with the minor elements on a few of the plants to see if there is any immediate improvement of plant color and new leaves. Anyway, a foliar spraying with fertilizer & minors should help the plants until the cause is corrected.

Re: Why are the leaves looking yellow?
 

Thanks for your input
The soil PH is 6.5
The supplement is the green bag, was given every couple of weeks in the rainy season (may till oct)
Contains Magnesium, Sulphur, Iron, Calcium and more..
The locals are telling us not to worry, that this is a normal occurence in this season and that the plants are strong and will recover .. fingers crossed

Re: Why are the leaves looking yellow?
 

Test foliar spraying the plants to see if they will green up.

You said: The irrigation is just an extension of the rainy season into the dry season. So you should be continuing the same fertilizer & compliments scheduled.

I think folar spraying of fertilizer may be better for you by reducing fertilizer loss & cost due to leeching.

Re: Why are the leaves looking yellow?
 

Absolutely, we currently use folear spraying in the dry season, much more efficient. We also have Longan trees so we already use that technique. Right now, it has been raining for two days so we have fed them all on the soil once more. Only the 8 months old Leb Mue Nam seem affected. The Namwah are currently looking fine but they have been over a year in the ground and are possibly in a place less exposed to a freak cooler gust of wind

Re: Why are the leaves looking yellow?
 

Hummm .... how deep is the water level? Dig an 8" (20 cm) to 10" (25 cm) diameter hole about 3 ft (1 m) to 4 ft ( 1 1/4 m) deep. Measure the surface to water level while raining and about 1 & 2 days after rain has stop. ... I wondering if the roots are flooded and if raised planting beds are needed or would help for that field.

Re: Why are the leaves looking yellow?
 

🙄 Last time the well digger was here he went down to 120 meters without finding any significant water. I have dug a 5 meter deep 6000 M3 water reservoir next door to the bananas in question, no water whatsoever when digging down and had to film it with LDPE to hold water. Thanks anyway for the kind brainstorming.
Interesting to note that on the night of Dec 21st, the temperature on Doi Inthanon mountain, 2565 meters summit fell to minus 1°C . Its only 50 clicks away and we could have had some unregistered cold drafts that night from the northwest which could explain sudden cold damage.

Re: Why are the leaves looking yellow?
 

General yellowing of the leaves is not cold damage. The cold effected parts of the leave will turn brown while the un-effected parts will stay green. See this post for reference http://www.bananas.org/f2/what-do-af...tml#post311850 ... Frost bit or frozen parts of the leaf will turn dark green (cooked???), then blackish, then brown (dead) within a 2 or 3 of days.

Re: Why are the leaves looking yellow?
 

A well driller is not looking for surface water or the surface water table. So water is ether draining way very slowly flooding the roots for days at a time; or draining away so quick the water is leching away the fertilizer & nutrients.

Re: Why are the leaves looking yellow?
 

I was thinking water problems... Bananas are much more sensitive to over watering in the cooler seasons. A light watering once a week should be plenty during cooler weather. (Which is anything under 65. Once it's over 65 degrees F 24 hours a day a few days it's safe to water more.)

Re: Why are the leaves looking yellow?
 

some of my bananas looked like his pic after it dipped down to 41f. they greened back up again when it got warmer. but some parts of the leaves turned yellow instead of green. the bananas that did it were all of my dwarf reds, gros michels and my kandarin. here is a picture taken about 2 weeks later of some of them.



also in the picture are namwas, mona lisa, manzano, Brazilian, sumatrana x, pisang raja, lady finger, sweetheart.

there is one not in the picture, my snow banana, the leaves turned in the mid 40s. they never greened back up again.

Re: Why are the leaves looking yellow?
 

Continued thanks to everyone for the invaluable shared experience.
We have not been watering more than once a week since the cold has arrived. As you can see, the soil looked really dry at the beginning of the week when I took the pic of the sword suckers. Yesterday and the day before we had continuous light rain and warmer temperature. Some of the leaves are starting to look like the one in the photo.

Re: Why are the leaves looking yellow?
 

It's cold and dry weather stress.
It's that simple.
Most of my bananas look like that now. Some varieties look worse than others.
The solution is stable, warm, moist weather! ;)
Until that happens, not much for you to do.
Feeding is a waste of time and money, when there is no heavy active growth.

Re: Why are the leaves looking yellow?
 

Thank you :08::lurk::0517:

I sure feel better reading your comment!

I now believe the problem was caused by Wind Chill

Cheers :nanadrink:

Re: Why are the leaves looking yellow?
 

Same here. A lot of mine look exactly like yours. It happens every year in the fall. Some varieties like Veinte Cohol, Nino, patupi, etc do this and others do not. My opinion it is cool weather stress and possibally lower humidity. Fall is my dry season in pure sand. So not a water issue for sure here!

Browning of the leaf edge and the leaf starting to curve down. Kinda like you would cup your hand palm down. That’s the sign i look for in overwatering or flooding to the roots. I’m sure there is a better way to explain it haha.

Don’t worry new leaves should look better soon! Good luck. Louis14

Re: Why are the leaves looking yellow?
 

if he's just startin to get a little cold he's going to look better a whole lot faster than us.

Re: Why are the leaves looking yellow?
 

The cold has passed by for now, 19°C at night and 30°C in the afternoon.