Accuracy of pH Meters

[WB2ORJ]

I have large (12' x4' x 2') raised beds with good quality topsoil and local nursery compost. I have planted my usual mix of tomatoes, peppers, squash, etcv and they just look kind of pale and struggling. I gave them a 24-8-16 soluble fertilizer about a week ago. I have several of those 2 metal probe meters, pretty good for moisture but all read pH as extremely alkaline. With compost shouldn't it be acidic? Do I need to add sulfur??

 

[Luis_pr]

Depends. Are they getting enough sunlight? what are your overnight temps like? any cold temps? rainy/cloudy weather? My soil is pH 7.6 but tomatoes do not mind if planted with lots of organic compost. But it has been raining like crazy and has been cloudy a lot so they are not producing much or growing much (compared to previous years).

Does the pH meter give you numeric results? The ones that do not have numeric results are hard to work with because pH is a logarithmic function and numeric results are more useful to me when interpreting the data.

 

[DirtMechanic]

my stick meters are best the day after a solid rain. Neither when the soil is wet nor dry, rather freshly drained and moist. Distilled and rain water can show a 6pH. Also, stripping the oxidation from the metal of the probe with an acid like a vinegar bath can be a big deal. I would test the meters against a control before sulphur. I fell into that trap once.

 

[NigelJ]

Personally I wouldn't touch one of the two metal probe pH meters with a barge pole (UK), very long stick(USA).
For the home gardener the cheapest solution is indicator paper or an indicator solution. Both of these you need to take a sample shake with water and allow to settle then measure; reading may be affected by high solution colour.
Next up would be this type of device https://www.amazon.co.uk/Essentials...65b7e11ee88726f1d5904809d73f66&language=en_GB can be calibrated as required with buffers at pH4 and pH7.
After this you start to move into laboratory type pH meters costing a lot more money and capable of measuring to several decimal places if calibrated accurately and looked after.

 

[headfullofbees]

Taste the soil, if it is just sweet, it is fine for most things; potatoes will stand quite bitter soil.

 

[Tetters]

Our soil is very alkaline. We don`t ''amend '' it at all. We grow almost every vegetable and fruit with no trouble whatsoever.