On 13/02/2012 19:32, JakeD wrote:
Hi all, I just did a soil test on my newly created veggie beds.

Here is the result:
Alkalinity: pH 8.0
Nitrogen: sufficient to slightly surplus
Potash: deficient

...and then there was the Phosphorous test which is the puzzling one! The
liquid was supposed to turn blue, to a greater or lesser degree, but it
didn't! It turned a very pale amber (the colour of the average lager or
cider). What does this indicate? Extreme phosphorous deficiency??

Dunno, but I would hazard a guess that the indicator they used preferred
adsorbing onto the clay particles to staying in solution.

The test kit is called a "Mini Soil Test Kit", containing four vials, each
with a different clour cap, and two each of four different chemical (each
in a capsule, which you pull in two and add content to the liquid in the
vial).

I followed the instructions to the letter. My soil is somewhat clayey and
sandy and has had a fair bit of last years compost dug into it.

What is the cheapest way to add potash and phosphorous (assuming I need
it)?

In a clay soil I probably wouldn't worry too much about supposed
nutrient deficiencies in a test kit. The test only measures easily
soluble components, but a lot of the goodness of the soil is locked up
in very fine clay particles which plants roots can gradually access.

Cheapest way to add some potash is the ashes from a bonfire or wood
burning stove. No coal or CCA treated timber though! A bit of unburnt
charcoal does not harm either - onions seem to love it on clay soils.

(Coal ash contains to much boron which is bad for plants and heavy
metals that are bad for us)

You probably don't want the more obvious and expensive garden centre
potassium nitrate since you are already surplus in nitrogen.

--
Regards,
Martin Brown