How to use lime testing kit

[chaos]

Made up a budget line testing kit got some test tubes and a rack of eBay. Got a fishing box in a local farm sale for £3.Had some soil indicator and barium sulfate from at @Mounty. Had some great fun with the kids testing the pH of various household foods and cleaning products but do not know the best way to test soil please could you include quantities as I hate to think I might be using too much product. I have looked at many pH colour charts and it is surprising how different 6.5 fairies in colour but I reckon the if I put some indicator with some distilled water that would give me a base of 6.5 to work from,am I correct any other tips would be greatly received.

 

[Mounty]

Try orange juice, coke and onions. Skin is about pH5.0
Basically, the indicator with or without distilled water should read neutral at 7.0.
You don't need much soil in the tube (Say 1 tea spoon max) but it needs to be as friable/crumbly as possible to help it mix well. Then 2 parts indicator (incl. distilled water) to 1 part soil as a rough guide. Shake vigorously and wait for it to clear. Barium sulphate will help it clear quicker. I would describe 6.5 as a mid green but everyone sees it differently. Don't get too hung up on 0.1 differences until you've done a bit. If you can tell the difference of 0.5 increments that will help you with lime applications. The more you do, the better you'll become at judging readings more accurately.

 

[chaos]

Roughly how much indicator with 20 ml of water.

 

[Mounty]

1:1 so 20ml of water = 20ml of indicator. Make sure its always distilled, never tap water.

 

[chaos]

So could you pre mix the water and indicator for a long time.

 

[Mounty]

Yep, should be fine. Just keep it in the dark when storing.

 

[Macsky]

Does it have have to be distilled water, will deionised water be ok? @Mounty

 

[Mounty]

It really needs to be distilled @Macsky - Subtle differences between the two. pH of deionised is 7.0 (neutral) when bottled but pH can change when the water exposed to air which may effect your result.
If you haven't got any to hand, just use neat indicator solution temporarily.

 

[An Gof]

It really needs to be distilled @Macsky - Subtle differences between the two. pH of deionised is 7.0 (neutral) when bottled but pH can change when the water exposed to air which may effect your result.
If you haven't got any to hand, just use neat indicator solution temporarily.

Every day’s a school day, I’ve been using deionised for 30 years

 

[Macsky]

What sort of places do you find distilled water?

 

[Mounty]

Pretty easy to get. http://darrantchemicals.co.uk/disti...MI5enD8uzz2AIVr7ztCh1d-wNnEAQYASABEgLo5_D_BwE failing that, collect some steam from you kettle.

@An Gof - I did say it 'may' effect your result. Then again it may not. I don't know how long it needs to be exposed to air for this change to take place but can't imagine it would be that quick. I think the deionised water has hydrogen ions in it so this is obviously a factor too..

 

[An Gof]

Pretty easy to get. http://darrantchemicals.co.uk/disti...MI5enD8uzz2AIVr7ztCh1d-wNnEAQYASABEgLo5_D_BwE failing that, collect some steam from you kettle.

@An Gof - I did say it 'may' effect your result. Then again it may not. I don't know how long it needs to be exposed to air for this change to take place but can't imagine it would be that quick. I think the deionised water has hydrogen ions in it so this is obviously a factor too..

Been doing a bit of googling on the subject. It’s all quite involved and rather fascinating.
Easy way out is to test the water with the indicator first ....... at least that will give you a reference point.

 

[Mounty]

Yep, its all good practice. If any element that you add to the soil in the tube (barium sulphate, water or indicator) is not 100% the test won't be reliable.