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Soil analysis

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Soil sample
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What kind of soil do you have?

You can use different methods to identify the texture of your soil.

Laboratory analysis

A laboratory analysis will tell you about the texture of your soil, its nutrient content, its acidity (pH) and how much organic matter it contains. The test results and the requirements of your plants will help you decide what quantities of amendments and fertilizer you need to add to your garden. The Montréal Botanical Garden does not offer this service, but it is available at many garden centres. You should be given recommendations along with your test results.

You should have the soil in your lawn and flower beds tested every three to five years, and your vegetable garden soil tested every two to three years. It is best to always have it analyzed at the same time of year, so that you can compare the results.

It may take several weeks to obtain your soil test results. You may want to take your soil samples in the fall, so that you can make the recommended changes the following spring.

How to take a soil sample to have it analyzed

First decide where to take the sample. The site should be fairly uniform in terms of drainage, topography and type of plants. Otherwise, you will need to take more than one sample – for instance, from one flower bed and from the lawn. For each sample, take a bit of soil from several spots, ensuring that you have at least 250 g (1 cup) of dry soil in all. For large sites, it is best to take small amounts from 10 to 15 different spots, zigzagging across the site. Proceed as follows:

Using a clean rounded spade or bulb planter, take a bit of soil to a depth of 15 to 30 cm (the depth to which plant roots extend). Place the soil in a clean container. Remove any stones and plant litter, without touching the soil with your hands. Do the same for each soil sample. Using a clean trowel or other tool, stir the soil in the container and allow the entire sample to dry out. Once dry, it is ready to be analyzed. If you take more than one sample, it is a good idea to identify or number each container.

Caution! Don’t take samples:

  • immediately after fertilizing plants or amending the soil,
  • from overly damp sites,
  • near roads where deicing salt has been used,
  • near fields and ditches,
  • from sites where manure or lime have been stored.

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