Test For Soil pH

Soil Test Kits For Acid or Alkaline Soil Types

The majority of plants do best in a 'pH' of about 6.5, but a range of 6 to 7 is acceptable for most. If your soil type is outside these limits, or you want to grow plants which prefer and alkaline or acid soil type, you will need to adjust the 'pH' of your soil.

Measuring the 'pH'
The only practical way of accurately testing the pH of your soil is to buy a soil testing kit from your local garden centre - they are cheap and surprisingly accurate. Most pH test kits work on the same principal of adding a small amount of soil to a syringe which has a filter in it. Add some of the special 'pH' testing fluid to the syringe and squirt the resulting mixture into a test tube. Compare the colour of the mixture to a colour-coded chart and you will then know the 'pH' of your soil.

The kit in the picture is a chemical one, but there are also easier and cheaper versions, click here to buy one of these from our recommended suppliers.

The other alternative is to ask your immediate neighbours who may have carried out their own tests on untreated soil.

Raising The 'pH' - Make Soil More Alkaline 
The 'pH' of a soil can be raised by adding lime. Their are several types of lime available each one doing the job, but in different ways. 

Slaked Lime - the most commonly available, it does the job well. Often simply called 'garden lime' on the package. Lasts about two years.
Ground Limestone - this is slightly better than slaked lime because it lasts longer in the soil (three years or more) and also contains magnesium. Often called 'Dolomite Lime'. More expensive than Slaked Lime.
Calcified Seaweed - similar to Ground Limestone, but it also contains more trace elements. The most expensive.
Hydrated Lime - often called 'Builders Lime'. It is cheap and does the job, but needs topping up each year.

When applying lime, follow the instructions carefully, too much and the plant roots will be scorched. It is better to apply smaller amounts at shorter intervals than too much in one go. Remember that altering the 'pH' of your soil is not an exact science, so absolute accuracy is not important.

Apply the lime about a month before sowing or planting and don't apply lime at the same time as manure - the result will be lots of ammonia gas which will deplete the soil of nitrogen.

Lowering The 'pH' - Make Soil More Acid
Adding compost and/or manure to the soil is the only practical way to naturally lower the 'pH' of your soil. It is rare that a soil type is so acidic this will not work.

If you really want to grow acid loving plants in an alkaline (chalky) soil, you will need to resort to raised bed system plant cultivation. The idea is that the chosen area of soil is isolated from the rest of the garden by enclosing it with a barrier such as railway sleepers. The barrier is placed securely on the ground and filled with acidic peat and soil. As long as the soil is kept acidic by regular additions of compost and manure, acid loving plants should grow well. 

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