Thursday 11 November 2010

Red Light Spells Danger

Last year I tried taking measuring the pH of the soil on my plot. It was rather frustrating and I ended up throwing my quick and easy probe meter away as it proved unreliable when compared to the chemical kit. Even with that bit of kit following the instructions proved no mean feat.

In principle the soil sample has to be dissolved (as much as it can be) in water and then you transfer some into the two chambers and add the chemical reagent to the clear chamber, shake again and compare the colour against the reference windows. 

All fine in theory BUT on site these manoevres require some preparation, forethought, dexterity, accuracy and recording.  Given that you've only got one tester pot you have to finish one test before you start the next. Yes, give the boy a star for stating the bleeding obvious, but this simple fact outwitted me as the suspension of soil refused to settle enough to allow sufficient light through the murk  for a reading to be taken  for hours, by which time the light and my enthusiasm were fading fast.  I took the pot home and set it down on a flat surface. The next day I got my one reading. And as the instructions and all the books say - don't rely on just one reading!


This year I got it sussed. Time for sedimentation was to be allowed for. I'd do all the fiddly bits at home, and I'd keep a photographic record. Simples! (sorry)

Here goes:

a. Collect half a dozen jam jars or similar with watertight lids

b. Label each with a scheme of the plot so that the location of the sample can be marked quickly and clearly
c. Take the pots + pencil to the plot
d. Take a sample at about 4 inches depth of enough soil to fill the bottom inch of your each jar at chosen locations spread across the plot and equal in number to the number of jars you have.
e. Replace lids and ensure each label is marked.

f . Return with the jars to the comfort of your home.
g. Add tap water to each jar and shake the pots vigorously to mix the soil and water, then leave to stand somewhere flat , out of harms way.

h. Have a good night's sleep while the sediment settles.
i.  When you have the time the inclination and have cleared a space in the kitchen, carry out the test as described above, on the now clarified upper portion of each sample in turn.

Here's some of my results

Well would you believe it my pH is a lot nearer neutral than I would have credited!!! But wait perhaps this is a false reading. Perhaps my tapwater is alkaline. Well just for reassurance I took a sample from the blueberry bed (which is filled just with ericaceous (acid) compost). This came up a lovely rosy pink! So clearly the chemical indicator is doing it's job.

End result?  I don't have to get neurotic about liming anymore!


  1. this isn't something I have ever done...and to be honest i don't think I'm going to. All my crops are growing just fine and all my fruit and trees are doing well too so I think I will leave well enough alone unless I start to have problems!!

    Glad you found you could do the same!

  2. I haven't done this either but it seems you need a science lab setting up to use the kits.

  3. Thanks for the tips on PH testing Mal!

  4. Good result Mal, no need to lime this time then. On chalk down here so I'm trying to make my soil more acidic. Suprising when you start looking into it how many fertilisers are alkaline which I can't put on my soil, not something I thought about before I tested my soil. Not sure how many gardeners who have chalk soil realise this.

  5. I'm glad of this post. I used the self-same kit last year, and often wondered if it was accurate. I am neutral, and if you have proven the kits accurate, then neutral I shall be.

    A bit like the Swiss.

  6. How igneous, Izzy.

    Craig, glad if my post has been of some reassurance to anyone. The idea was to demystify the process (But Tany and Sue I may not have fully achieved that!)

    Damo, I know you will overcome any challenge thrown at you - even a geological one.

    Iggy, whatever you are you're not neutral!