Why Gardeners Should Test Their Soil

Most New Zealand homes have at least a small garden or lawn, and many Kiwis are keen to grow trees, flowers, fruit and/or vegetables in their backyard. Soil quality plays an enormous part in whether your gardening is successful.

Starting a new garden

Before you plant your garden, it is good to test what nutrient levels are prevalent so you can add extras as needed for optimal growth.

If growing fruit and vegetables it's important to test for contaminants as well, as they absorb contaminants from the soil as they grow, and contaminated soil can stick to the outside of root vegetables which are ingested when the produce is eaten. If there are high levels of contaminants in your soil, those ingested contaminants can cause health problems for you and your family. 

Children are particularly susceptible to contaminants in soil. They are likely to be exposed to higher doses over a shorter time frame from playing outside, and ingesting an overall higher proportion of contaminants due to their lower body weights.

The history of your property and the surrounding area and the age of your house, can give you clues about what contaminants may be in your soil.

    Why are my plants dying?

    If you have an established garden and don't know why your plants are dying, it is possible that your soil is contaminated, the soil is lacking in nutrients or that your plants have been sprayed with toxic herbicides.

    As with planting a new garden, start by considering the history of your property and the surrounding area, the age of your house, and whether you or your neighbours have recently sprayed insecticides on or near your garden, as this can give you clues about what common chemicals and contaminants may be in your soil.

    A number of other things can cause your plants to die or be in less than ideal conditions:

    • Too much or too little water
    • Too much or too little sunlight
    • Too hot or too cold
    • Too much wind
    • Disease
    • Poor drainage
    • Poor soil structure
    • Development works in the area that have altered the water table or flow of surface water

    What should I test my soil for?

    We've put together a suite of test kits specifically for home gardeners and those conscious of their families health, which you can find here.