What is this "discolouration"on my Chinese Elm?

[hemmy]

Come and see for yourself.

I would be honored!

THAT would be amazing! A BonsaiNut meetup at Mr. Pall’s garden! (garden seems a woefully insufficient title for the trees that I have seen online).

Also an interesting effect of Mr. Pall’s super feeding regime (as he described on his blog and on this site), is the use of ammonium and urea in the box store liquid fertilizers which is acidic. This may have a great buffering effect on the water.

 

[bonsai-ben]

I use water from Orange County Utilities. That's Orlando FL water. For half my trees.

For the other half, I use a shallow well.

All the trees look the same to me, I water from the pot level down, I dont water the leaves, clouds tend to do that when they change color just fine for me and that's all soft water.

 

[petegreg]

That will never happen if you simply sprinkle some elemental sulfur on the soil. Trust me.

And I thaught chemistry was important in love... Fortunately we all are happy.

 

[milehigh_7]

I’d like to hear more about your experience with sulfur. How alkaline is your water, how much and often do you apply it to say a gallon nursery container, and do you use organics with your inorganic substrate (I’m assuming from your previous posts that you use DE and other inorganics)?

I have been using Espoma soil acidifier (mostly elemental and some gypsum derived sulfur) with decent results. Maybe I’ll get an expensive pH meter to play with for my birthday and do some leachate tests. I found the below article interesting. While it touts the ineffectiveness of sulfur to lower container media pH, the 3 reasons that it doesn’t work for short turnaround greenhouse plants are the exact reason it could work for our application.

1. Bacteria have to oxidize the sulfur to eventually convert it to sulfuric acid. Using organic fertilizer should assist here.

2. & 3. Time, greenhouse crops finish in 3-12 weeks, not long enough for bacteria to buildup and some sulfur can take months to breakdown. A few years in a bonsai pot should check this off the list!

https://www.pthorticulture.com/en/training-center/myth-series-sulfur-drops-the-ph-of-growing-media/

I do believe this place is the only place in the world that thinks this...

 

[milehigh_7]

Oh my water is about 8.5 - 9 for some odd reason bougs, lavender star, liquidambar, poms and many others that require a pH around 5.5 seem to do just great. Plus in DE the soil is about 7 soooo something must be off in that place's research.

 

[hemmy]

soooo something must be off in that place's research.

The sulfur must be working then. Their research seemed to be focused on short term greenhouse plants.

 

[Ingvill]

Pardon my late reply, I didn't even have time to turn my computer on this weekend.

Yes, I do fertilize. Once per week with organic liquids (brand; Biobact).
I give about 50% over the bottle's recommended dosage on all trees except the Dawn Redwood which gets the exact recommended dosage.
I water thoroughly every day though, water is really gushing out of the drain holes.

Would it be an idea to mix a little kanuma into my substrate mix (molar clay, pumice, kiryu & akadama) to lower the pH slightly?
They are all repotted this year, but I could sprinkle some kanuma on top of the substrate perhaps?

 

[hemmy]

Pardon my late reply, I didn't even have time to turn my computer on this weekend.

Yes, I do fertilize. Once per week with organic liquids (brand; Biobact).
I give about 50% over the bottle's recommended dosage on all trees except the Dawn Redwood which gets the exact recommended dosage.
I water thoroughly every day though, water is really gushing out of the drain holes.

Would it be an idea to mix a little kanuma into my substrate mix (molar clay, pumice, kiryu & akadama) to lower the pH slightly?
They are all repotted this year, but I could sprinkle some kanuma on top of the substrate perhaps?

I don’t think you have anything to worry about unless you start seeing signs of mineral deficiencies. I also don’t think that sprinkling a little on top would have much impact. Kanuma is reported to be more acidic than akadama, but various sources have shown that the pH range and difference between akadama varies. However if your water has low alkalinity, then it has a low buffering capacity. This might allow akadama and kanuma in your mix to have a greater impact than it does in my experience, where my water has high alkalinity and a large buffering capacity.

 

[Ingvill]

Okay, great!
Thank you all so much for all the information, I have certainly learned a lot

 

[my nellie]

That will never happen if you simply sprinkle some elemental sulfur on the soil. Trust me.

I’d like to hear more about your experience with sulfur... ...

Probably this is a silly question... I will post it though...
Do you know what (if any) is sulfur's impact on friendly fungi in the substrate?

 

[milehigh_7]

No I don't. I would suspect it's not great for it in large amounts. Sorry i plead ignorance here.

 

[Gustavo Martins]

However if your water has low alkalinity, then it has a low buffering capacity. This might allow akadama and kanuma in your mix to have a greater impact than it does in my experience, where my water has high alkalinity and a large buffering capacity.

This is very true and why pH measurements are mostly meaningless when water has low alkalinity. If you blow to a glass with low-alkalinity water your pH will drop readily. Agitate the water and the pH will rise again. Same on a pot. Plants breathe. With all the gas exchanges inside the pot, pH will vary if you have a low alkalinity.

Even on a rockpool (saltwater is quite hard), pH will vary throughout the day (raise by the day, lower during the night), due to balance between photosynthesis and respiration of all organisms therein...