Easy Home Soil Tests Every Gardener Should Be Doing

My family and I recently moved to a new house with plenty of gardens. In the past, I’ve been so eager to get shrubs and flowers into the ground that I never even stopped to think about the soil and how its condition would impact the plants. I’ve learned that when it comes to gardening, instant gratification isn’t best practice; patience is a virtue.

Because I knew nothing about the existing soil at my new house, I decided to find out what I was working with. Soil tests are something every gardener should be doing each and every season; a beautiful garden begins with healthy soil, and knowing more about its condition will also help you with plant selection. The testing process doesn’t have to be complicated; the few I performed at home were extremely cheap and easy!

Testing Soil Composition

Before doing any planting, it’s very helpful to know the composition of your soil. There are four main components: rock or mineral particles, organic matter, air, and water. Every garden has its own soil texture determined by a balance of the three main mineral components — sand, clay, and silt. Together, these three will affect how the soil absorbs water, nutrients, and air.

To determine what kind of soil you have, fill a glass mason jar with about two cups of earth from your garden. Fill the rest of the jar up with water, shake well, and then let it settle for about a day. You’ll notice sand will quickly fall to the bottom, silt will form the next layer, and clay particles will settle on top. Any organic matter will float on the water’s surface.

Once the soil has settled in the jar, the Compost Council of Canada recommends comparing the height of each layer as a percentage of the total height of the soil in the jar. For example, my test revealed that my soil was made up of about 40 percent sand, 50 percent silt, and 10 percent clay.

A fertile soil is usually balanced, meaning you will have fairly equal parts of silt, sand, and clay (ex: 30% sand, 40% silt, and 30% clay). This perfect equation produces what is called a loam soil. Any extreme will cause various problems. If your soil is too sandy, water and nutrient retention will be almost impossible. On the other hand, a clay soil will be more compact, meaning air and water will have a hard time moving through it.  

Testing pH Levels

Testing the pH levels of your soil will help determine what kind of plants will do well in your garden. A home testing kit is available at most greenhouses, nurseries or hardware stores. Again, this is so cheap and easy! I bought this one, which also allowed me to test the nitrogen (N), phosphorus (P) and potassium (K) content in my soil, the three main nutrients vital to plant life.

The results? My pH test revealed I have a slightly acidic soil in my garden, meaning plants like Magnolias, Rhododendrons, Holly, and Begonias should do well for me. Armed with the knowledge of whether you have acid, alkaline or neutral soil, you can choose plants that will thrive all season long. How great is that?

With regards to the NPK content in my soil, these are troubling times, my friends. My test revealed I have very low levels of all three essential nutrients. Luckily, there’s a fairly easy fix discussed at the end of this blog.

Soil Tests

Testing Soil Drainage

Finally, it’s a good idea to know what the drainage capacity of your soil is. To find out, all you have to do is dig a hole in your garden that’s about 1 sq ft wide and 1 ft deep. Fill it with water, and let it drain overnight. The next day, fill it again and mark the surface of the water for a reference of where you started. Use a measuring tape to record the depth of the water every hour.

An ideal drainage rate is about 2 inches per hour, but anything between 1 and 3 inches works well for most plants. Less than 1 inch an hour is far too slow, and more than 4 in an hour is ridiculously fast. In my case, I lost an entire foot of water in 45 minutes. YIKES. No wonder my existing plants looked so thirsty!

How To Fix Your Soil

Here’s the beauty about all of these tests: no matter what your soil type, pH, nutrient, and drainage levels, there’s ONE way to achieve more desirable conditions: compost! This is truly the magic solution to nearly all problems that ail your soil; you’ll improve drainage and water retention in your gardens, while also increasing their fertility and overall soil health. For beautiful blooms and healthy-looking plants, it’s recommended you add about 3 in of compost to your gardens at the beginning and end of every season.

I told you this entire process was going to be easy-peasy! Now that’s my kind of test.

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Catherine Sherriffs

Editor at Garden Culture Magazine

Catherine is a Canadian award-winning journalist who worked as a reporter and news anchor in Montreal’s radio and television scene for 10 years. A graduate of Concordia University, she left the hustle and bustle of the business after starting a family. Now, she’s the editor and a writer for Garden Culture Magazine while also enjoying being a mom to her three young kids. Her interests include great food, gardening, fitness, animals, and anything outdoors.