cover crop and organic trash, buried, on top. and time. You will never get the pH down to optimal for roses, but they will survive in the presence of plentiful organic acids. A good trick for me is to put 20 lbs or so of rotten wood in the hole every time I plant a tree. Works with 100% efficiency.

Hmm wouldn't adding sulphur help? I read that using ammonium nitrate also helps with nitrogen as well as bring PH down?

Can I pluck neem tree branches and put them into the plant hole?

Thanks.

for a while it helps. Do this: take a lump of soil, dry it and pulverize it. Put the dust in a bowl and pour vinegar on top. If it bubbles (it probably will) you will never be able to significantly and permanently alter the pH. My pH=7.7 soil makes small bubbles, so i just get what I can from the OM. Sure you can put any sort of branch into the hole.

Disclaimer: I don't grow roses, but I am trying blueberries, which need acidic soil, and my blueberries, both cultivated and wild, have survived several years now and fruited. In the pots, and in the "wild" I made a bed of peat moss and perlite. (Is perlite the little white balls?) That's it - no "soil".

How much organic matter is in that soil?

While glib is correct that anything you do to change a soils pH is only temporary adding the right amount of sulfur (to lower) or lime (to raise) a soils pH can last a few years. Yes, adding more of what is needed will need to be done, just as we need to add other nutrients to the soil to feed the plants growing there.

Sometimes adequate amounts of organic material can help with soil pH, but mostly that will raise that pH. For example, in my soil adding enough organic material to get the soil organic matter up to 6 to 8 percent will also change the soil pH from 5.2 to 7.2, or at least it has for about 40 years. Having adequate amounts of organic matter in the soil could also get the nutrient levels up to optimum.

Hmm yes the Organic Carbon that percent was mentioned at 0.17% in soil.

After reading what you said about Organic matter increasing the soil PH and reading somewhere that Cow dung has PH of 4 to 7... Do you think it would be wise to use Cow dung instead of just leaves as Organic matter?

Because what I am trying to do is not unbalance what is already over there. Just want to fix two or three things with one shot. That would be add organic matter as well as try to bring the PH to normal levels.

Thanks.

most probably you will be unable to change the pH. But if there is plenty OM, acid loving plants can survive in more alkaline soil. both quantity and quality matter. you get quantity by using whatever organic you can get, manure, leaves or wood. you get quality by growing a thick vegetation in there which will help the soil biology most.

Thanks a lot glib for taking time and answering it.

As you mentioned two or three times that I won't be able to ever change the pH I am thinking of just tossing this soil (upper 24 inches) out and get some new soil. Because don't want to get stuck with high pH soil and down the road after 5 years or so think maybe my plants are performing good due to this soil. It always pricks at the back of the mind. I have like 700 sqft so for $100 I can get that soil hauled away and get new one in.

0.17% OM is extremely low, so adding organic matter will help.

Low P can affect flowering, but compost will add P. If you're not having problems with flowering I wouldn't bother with chemical P fertilizer. You need to get the OM up anyway and good compost will add plenty of P.

What is the texture of the soil? Sandy, silty or clay?

Saying roses prefer acidic soil is like saying maples are 15 ft tall. Some do. Some don't. 8.1 is high for roses, but adding organic matter should bring it down enough to make many roses happy. Avoid roses budded onto multiflora rootstock. Dr. Huey or Fortuniana should be fine. If you want more specifics, ask in the Rose Forum, or the Antique Rose Forum. The Antique Forum has a lot of Californians who deal with fairly similar conditions.

0.17% OM is extremely low, so adding organic matter will help.

That's not OM, it was reported as Carbon content, Tox.

in fact i refrained from commenting on OM because I have no idea what 0.17% C means in terms of OM. But it can not be a large number, most organic molecules are more than 50% C.

As a rule animal manures do tend to be near neutral to a bit alkaline and can help make low pH soils closer to neutral. While manures are a part of the whole organic material collection they need to be added to soil along with vegetative waste in about the same ratio (1 part manure to 3 parts vegetative waste) as in a compost pile.

Adequate amounts of organic matter in soils (about 6 to 8 percent) buffers soil pH over time. However, adding sulfur (to lower soil pH) or lime (to raise soil pH) is faster even though they can take 6 months to do that.

There is no need to toss the soil you have and buy something to replace it. A soils pH depends on a number of factors and people living in the northeast tend to have acidic (low pH) soils due to the amount of rain while people in the southwest tend to have alkaline (high pH) due to lack of rainfall.

This article may be of more help understanding soil pH.

http://www.esf.edu/pubprog/brochure/soilph/soilph.htm

All right, soil organic carbon does not equal soil organic matter - agreed. It's like measuring the amount of carbon in carbohydrates (generic formula CH2O) - the % carbon will be less than 100% obviously. Rule of thumb for soil OM is 58% C. So soil OC/0.58 = soil OM, in this case that gives 0.29%.

This is still extremely low compared to a recommendation of about 5% for good fertile garden soil. Which is why I didn't bother with the conversion in the first place. Sorry for not showing my work. ;-)

Lol. Apology accepted.

I knew you knew. A long time ago I decided that it's best to be clear and not generalize. People take it a run with it. Then sometime down the road it gets passed on. Like the "telephone" game. So, I'll often stick my big nose in for clarification.

For example, a person asks, "I've bought some ammonium sulfate fertilizer for nitrogen, how much do I put on my lawn?"

Someone answers "5# per thousand square feet."

A couple of weeks later, someone says, "I bought some urea fertilizer for nitrogen, how much do I put on my lawn?"

Someone answers, "I just read about this a couple of weeks ago, you want to put down 5# per thousand square feet."

Currently am incorporating lots and lots of compost into the soil.

Additionally I have got 1 Pound of Sulphur 80% and will be trying to add some to the soil.

Ongoing plan is to use Mono-ammonium Phosphate (MAP) as I read that it has a side effect of acidifying soils where it is used. And I just want that.

Thanks.

This one said 3.5 lbs for 10x10 area to bring PH from 8 to 6.5

https://garden.org/nga/calculators/index.php

I thought will start off with 1 pound and see the results in some months.

Don't know if that calculator is wrong or something.

Thanks.