"Mark" wrote in message
oups.com...
I have bought an electronic soil tester. Measures PH level

This will not be very accurate as it depends on moisture content to get a
reading. Dye based indicators are much better and probably cheaper.

and Nutrient level (fertility).


I believe that you have been deceived. It is simply not possible for an
electronic meter to determine fertility as a single reading. I am assuming
this is portable device with a single probe, in a laboratory it is feasible
to have one machine that would test for many substances. Even then the
amounts of each major nutrient (at least) need to be reported separately.
The matter is far too complex involving about ten major and minor nutrients,
plus issues of porosity to air and water, and the possibility of the device
being confused by substances which are either not nutrients or downright
poisons, for one figure to tell you what is going on. I would love to know
the make and model of this gear and what evidence they have for it working.


The PH it generally shows OK around 7.

This is OK for many plants but not all. There is a signifiant proportion
that do better at more acid levels.

But fertility is low.

1.What should I do now with plants potted in containers? Is adding
standard 15-15-15 fertilizer enough for that?

Depends on the real fertility of the mix and the type of plant, different
plants have different needs.


2. When next time I prepair soil for containers. I usually mix half a
soil from the ground and half the compost I got from the dump. Should I
mix 2 parts compost to 1 part soil?, So I do not have to add fertilizer
right away after planting?


It depends on the nature of your natural soil and what you get from the
dump. If the latter is just rotted munched up vegetation trimmings it will
improve your soil's texture but may not add much in the way of nutrients.

David