Your Soil pH Levels

What is soil pH
I'm sure you all remember back to high school chemistry class and learning about the pH scale and testing levels with litmus paper. Well this isn't so different. The pH scale tells us how acidic or alkaline something is. Ranging from 0-14 with anything below 7 being considered acidic and above 7 being alkaline with 7 being considered neutral.
Our soil has a natural pH level with the majority of NZ's soils being slightly acidic. You can pick up a very cheap pH soil testers from local hardware stores to be able to test your soil's pH.

Why is it important
Your soil's pH level is one of the biggest determinates of whether your plant can access all the nutrients it requires. Even if all the nutrients are present in the soil if the pH level isn't right it can affect the plants ability to draw up those nutrients. As a general rule most cut flower varieties like a pH level between 5.8-6.5.   

How to increase your soil pH
If you have found that your soil is slightly too acidic the best way to increase your pH level is through adding lime. Lime comes from limestone and is made up from calcium carbonate. When you add lime to the soil the calcium carbonate dissolves slowly and the pH level of the soil goes up. Dig the lime into the soil to roughly 150mm below and it will take about a year to dissolve. You can apply on top of the ground but this does risk run off. 

Benefits of Adding Lime
Lime will directly help the soil through adding more calcium into it. It will also increase the soils pH level allowing plants to take up more nutrients. 
Lime indirectly helps the soil through attracting more earthworms and encouraging soil microorganisms to eat the humus and make more nutrients available in the soil.

Application Rates
There aren't too many negative side effects if you over apply lime, but you can recheck your pH levels too ensure they are not becoming too alkaline. 

When applying you will first want to take a tape measure to the space you are applying the lime too. Measure the width and length and multiply this together to get your square meterage. Once you have that you can assess what type of soil you have and use the application rates in the table below.