Hello all,

I planted two redwoods, both a Dawn Redwood and a Coastal Redwood. I planted them with substrate, with some lava rock on top to keep the substrate from flowing out, they were both seedlings that were already 4-6 months old. I had an issue where some of their leaves started to yellow, and fall off, I think I watered them plenty.

I looked into Redwoods and some potential causes, and read that they liked acidic soil. I have a meter that reads how much light, moisture, and the ph balance of the soil. When I checked both of them, the soils came up as pretty alkaline.

The ph came up as 7, and I have read that they prefer a ph of 5, so that they can get iron. I do have some slow release fertilizer pellets, but the minerals in it are nitrogen, sulfur, magnesium, boron and copper.

So what is the best way for me to get them iron, or get the soil substrate to the right ph levels? (I read that putting coffee grounds into the soil could add acidity, but I am not sure if that is accurate or the proper way to help my Redwoods, and I also have read things online before that were wrong, and laughed at here lol so I came to ask the question before I tried that)

What kind of soil is it in today?

Whats the ph of the water you use?

It is in substrate, this mix is Sifted Akadama, Pumice, and Lava rock.

The ph of the water here is 7 on my meter. (I don't know how accurate it is, it is a 3 way meter). The report on water quality my city put out, states that the water here fluctuates from 6.5 to 8.5.

I have had the the trees outside since I planted them, and they have gotten rain water 2-3 times. But I have been supplementing them with water from the tap to make sure they get enough. Do they make lower ph water that I can buy specifically for this?

I am not experienced with the species and cannot tell you if lower ph will make any difference or not.

But this is your options for lowering the ph:
Put some kanuma in the soil mix. However now is not the time for repotting in thr northern hemisphere.

If your rainwater is safe, collect and use as much as possible.

If you thimk you need lover ph, try humic acids. You might find concentrated at aquarium stores. But it can be done sheap and easy with materials from nature. Were you are in the world might dictate how easy it is.

I think most important is not to change to much of the PH.
Just see if it grows, if it is green and lsuh, no need to change anything.
Tree will let you know if it is happy or not. By the color of the leaves.
If there are signs of yellowing or cholorsis, then check PH.
Most elements can be taken up in a wider range of PH anyway.

Miracle Gro has a fertilizer for acid loving plants. I don't know how to reach a goal pH.

I bought some kanuma, the brand on Amazon that I get most of my substrate from offers it as well. But I am thinking, maybe that's better for next season? Since re-potting season has passed, better to make sure the redwoods have enough water, and see if they survive, and then repot it next year with kanuma added?

Humic acids were much more expensive, and rainy season is really only 5-6 weeks away here, so I hope to collect quite a bit of rain water, and hopefully the redwoods survive.

BentoSalesBoy wrote: Humic acids were much more expensive

Did you try searching for oxalic acid, thats what i use for in my tabwater for my Azalea.

I will give that a search and try as well!

The tap water where I live is seriously alkaline. So I just add 1 tablespoon of lemon juice to 1 gallon of water. I also add 2-4 teaspoons of Epsom salts per gallon. I also have iron pellets, which I sprinkle from time to time as instructed. Almost everything I water grows great, including Dawn redwood. (The only problems are Sweet broom, Lilac and Mealy sage).