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What is It?

Soil pH is simply the measurement of soil acidity or alkalinity measured from 0 (most acidic) to 14 (most alkaline) with 7 being neutral. Each unit of measurement on the pH scale goes up or down exponentially with each step up or down representing 10 times the difference. A soil with a pH of 5.0 is 10 times more acidic than soil with a pH of 6.0 which is 10 times more acidic than a soil with a pH of 7.0. Soil pH has the tendency to change over time with the additions of things like fertilisers and mulches and can even vary in your own back yard due to concentrations of rust or chemicals that have collected over time. You can find out your soil pH with a soil-testing kit, which you can get from your garden supplier. All plants are affected by extremely acidic or alkaline soils but there is generally a wide variance of tolerance. The best pH range for most plants is 5.5 to 8.0.

So how do you fix issues with soil ph?

The first and most obvious way to fix the problem is to simply buy plants that suit your soils pH level. Acidic soil lovers are plants like Azaleas, Camellias, Gardenias, Citrus and Magnolia. Plants that love Alkaline soils include Kangaroo Paws, Dahlias, Ivy, Bottle Brushes and Poplars.
The second option is to supplement your soils, which is often a much easier task than some people expect.

Acidic soils.

To fix acidic soils add finely ground agricultural lime, how much you add is dependent on how finely ground the lime is and how acidic your soils where to start with. A safe bet is to sprinkle the lime like you where icing a donut, it’s always best to do too little rather than too much. Once you have added your lime water it in and check your soil pH again in a week, repeat if necessary. Other ways to increase pH is to add Mushroom compost which has a high lime content and will help you soils in the long run but it is not as potent as pure lime.

Alkaline Soils.

To fix alkaline soils add Iron Sulphate at a rate of around 100g per M2, water in well and again recheck pH in a week, repeat if necessary. Other, more organic, solutions include certain mulches like Pine Bark or Eucalyptus Mulch. Also the decomposition of organic matter like compost, plant matter and manure will also decrease your soils pH through the decomposition process.

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Categories:   Landscaping