Soil pH question

[Brekel]

I have a question on adjusting soil pH.

I currently have some seeds and cuttings growing, which are all in a mix of peat moss, perlite and propogating sand.

The cuttings (melaleuca and huon pine) look healthy - huon pine is green (apart from one that dried out due to error), the Mel is putting out new leaves after about 5 weeks.

The seeds are doing ok:

• English oaks (6 weeks now) have roots through the bottom of pots but haven't broken the top surface yet

• Cedrus seeds germinated in fridge, then planted 12 days ago. Broke through the soil surface yesterday

I've never tested soil pH before. I use to have a pH meter for other purposes but don't any more. I have a couple of pH test kits. My tap water tests as very close to 7 (maybe 7.2). I collected some water that drained through the pots with the acorns, and it tested as around 4.5 which I would think is too acidic.

I havent tested the others, and the mixes could be slightly different propprtions but the same ingredients. The only difference is the acorn pots had very open bases so I put a few strands of sphagnum moss over the holes to stop the mix falling out, bur I wouldn't think that would affect the readings greatly?

Is a pH that low going to cause issues? And with the seed that are only just sprouting, is it possible to adjust it in a way that won't harm the new seedlings?

Thanks,
Brett.

[Brekel]

The only other point to note is that this was tested early in the morning. I don't know if this makes a difference to the reading for plants, but I know that with some aquatic environments and fish tanks pH is lower overnight/early morning.

[treeman]

Pest moss has a pH of around 3-4. So you mix is probably around that unless the sand has any carbonates in it.
Usually not a problem for propagating. Peat moss has a very high buffer capacity so water of pH 7 will only change it very very slowly.

[Brekel]

Thanks Treeman.
As long as my seeds are happy, I'm happy

[shibui]

While the plants are growing well I would not be trying to change the soil. Trees are usually quite resilient and even though 'slightly acid' is generally recommended most trees will grow in a wide range of soil pH.
I have only ever tested soil and potting mix with the kits. I have not heard of testing run off water so I am not aware if that is directly related to the soil pH or whether there might be other factors affecting that reading.
It is possible to alter the pH of potting mix with trees growing but there is huge possibility of going too far or creating a problem with the amendments.
You should also be aware that pH of potting mix does change naturally over time so what you read now will not be the pH for the entire time those plants are in the pot.

By the way, it is quite normal for a long delay between oak roots and the shoots showing above.
And another, possibly relevant bit of trivial info: At my last property the trees were watered with well water and grew quite successfully for many years except azaleas. After the second hot water tank and a few taps dissolved I tested the water. It had a pH of 4.3 Most people would expect that water to be almost toxic to many plants but they seemed to do fine. Point is that optimum is not always necessary.

Have fun with the seeds and seedlings.

[Brekel]

..
After the second hot water tank and a few taps dissolved I tested the water. It had a pH of 4.3 Most people would expect that water to be almost toxic ...

Thanks Shibui.
Your last place sounds a bit like my last one.
I never suspected anything until my daughter with blonde hair stayed over. After she washed it in the shower, it went green!
A bit of invstigating and I found the tank water was around pH 4, and was disolving the copper in the solar hot water heat exchanger
The shampoo precipitated the Cu in her hair.
Thankfully it was just a short term rental during a big move, and a pack of bicarb in the tank was a short term fix.

[shibui]

I also had a blonde/green haired daughter for nearly 17 years - now grown up. She had a more sensitive pallet and complained about the taste of the water but no- one else could understand what she was talking about. Maybe we can get her to test potting mix?
Eventually I put a calcite filter on the supply line which fixed the pH but left calcium deposits on bonsai pots, kettles, etc.

[Raging Bull]

Hi Neil, would your daughter have to taste the potting mix to test it?

[shibui]

That's the inference I was making but joking aside, before the days of testing kits and meters many of the farmers and gardeners did taste their soils to assess the acidity. That's why we refer to 'sweetness' of soils. They were tasting for sweet or sour to assess pH.

[Brekel]

I wonder if they also fertilized with manure