A few weeks ago I bought a bag of Westlands John Innes No3 compost for
mature plants. Out of interest while I was checking other part bags of
compost with a digital pH meter, I found that the said compost was
reading 4.5, which is very acidic.
It is a sandy brown colour with sand and loam added.

More recently I bought a bag of Wetlands Ericaceous compost and when I
opened it, I saw that is was the same colour as the JH No 3. On checking
the blurb on the outside of the bag, I read that it also contains sand
and loam. The pH reading was also 4.5.

I wonder how you could tell the difference if they weren't in different
bags, although it doesn't matter as I just used both types for some acid
loving plants.

In article <iq8tk2Fjt66U1@mid.individual.net>, RobH <rob@despammer.com> wrote:
>A few weeks ago I bought a bag of Westlands John Innes No3 compost for
>mature plants. Out of interest while I was checking other part bags of
>compost with a digital pH meter, I found that the said compost was
>reading 4.5, which is very acidic.
>It is a sandy brown colour with sand and loam added.
>
>More recently I bought a bag of Wetlands Ericaceous compost and when I
>opened it, I saw that is was the same colour as the JH No 3. On checking
>the blurb on the outside of the bag, I read that it also contains sand
>and loam. The pH reading was also 4.5.
>
>I wonder how you could tell the difference if they weren't in different
>bags, although it doesn't matter as I just used both types for some acid
>loving plants.

Assuming you mean Westland, don't touch them, nor their premium brand
(JA Bowers) - the latter was OK until it was taken over. Their JI
Seed compost was essentially pure silt (I tested it), and the JA Bowers
version was little better. I did the testing following repeated
germination, emergence and survival to potting out failures, which
I rarely had had previously (or since).

Regards,
Nick Maclaren.

On Mon, 13 Sep 2021 13:13:53 +0100, RobH <rob@despammer.com> wrote:

>A few weeks ago I bought a bag of Westlands John Innes No3 compost for
>mature plants. Out of interest while I was checking other part bags of
>compost with a digital pH meter, I found that the said compost was
>reading 4.5, which is very acidic.
>It is a sandy brown colour with sand and loam added.
>
>More recently I bought a bag of Wetlands Ericaceous compost and when I
>opened it, I saw that is was the same colour as the JH No 3. On checking
>the blurb on the outside of the bag, I read that it also contains sand
>and loam. The pH reading was also 4.5.
>
>I wonder how you could tell the difference if they weren't in different
>bags, although it doesn't matter as I just used both types for some acid
>loving plants.

IME Westland composts are rubbish. I had some of their ericaceous a
few years ago and it was like muddy sand. Might have been OK for
aquatic composts for use in ponds etc, but I lost a lot of azalea
cuttings when I used it.

Small privately-run nurseries often stock good-quality composts, but I
avoid the big chains. Melcourt composts are pretty good, also Vitax
and Humax.

--
Chris

Gardening in West Cornwall, very mild, sheltered
from the West, but open to the North and East.