Gardening begins with the soil

It seems that gardeners brag about their flowers, their big tomatoes and their
beautiful trees but one of the things they
don't seem to brag about is their dirt!

Good dirt should be the envy of anyone who puts plants or seeds in the ground with great expectations of the bounty to follow.

Dirt—OK, soil—is the stuff that makes it all happen. Soil is incredibly complex. It contains minerals, organic material, liquids, gases and an amazing array of living organisms from those you can see such as earthworms and grubs to the microscopic such as fungi, molds and bacteria.

Here in northern Minnesota you will find soils that range from sandy to clay with large mineral particles to microscopic mineral particles often within yards of each other. Also, soil here is usually very shallow. When we lived in the Red River Valley, we found topsoil up to 4 feet thick! Here 4 inches is typical, after all it is only 10,000 years old, the blink of an eye geologically, and up to the late 1800s was deep forest.

There are several basic things you need to know about soil to enhance your success as a gardener. First, how much organic material is in the soil? When soil is newly turned and you pick up a handful and take a good sniff, the wonderful aroma that should meet your nose is the result of the life processes of all the living organisms and decomposition of organic matter. Remember that indiscriminate use of pesticides, herbicides and other chemicals kills the things you can't see as well. Composting and mulching with organic material is the single best way to increase organic material in the soil and improve texture. Organic material provides nutrients, retains moisture, increases tilth. Strive for loam, a well-balanced soil texture.

Second, what is the chemistry of your soil? One aspect of the chemical makeup of the soil is pH. This is the acidity or alkalinity of the soil. All plants thrive in their own unique range of pH. Blueberries or azaleas thrive in acid or "sour" soil while most veggies and fruits like a pH range from 5.5-7.0. The other chemical components you must know are the presence of the primary nutrients; nitrogen, potassium, and phosphorus (NPK). Don't assume your soil needs fertilizer if your plants are not doing well. A soil test is the only way to know fertility and pH. A test will also give recommendations for fertilizer and modifications for pH based on the plants you place in it.

Third, what is the soil texture? Coarse, sandy soil drains moisture and nutrients rapidly away from the roots and into the ground water leaving plants thirsty. Clay soils retain moisture and reduce necessary gases such as carbon dioxide and oxygen at the root level. One might think that adding sand to clay soil would solve this problem. Well, clay and sand make good mortar but poor soil! The addition of organic matter is the best way to modify texture.

You may want to give up and just have a load of "black dirt" hauled in. Be careful; if you don't know where it came from, you don't know what's in it. A friend had a load of black soil hauled in for the yard and garden. After the grass died and the tomatoes wilted, a detailed soil test revealed the presence of Atrazine applied years ago to corn ground. Expensive lesson! Unfortunately, "topsoil" is an unregulated commodity. The attention you give to your own soil will yield the best results.

Information on these horticultural topics can be found in the Yard and Garden section of the University of Minnesota website—

By Wally Peck, Beltrami County Master Gardeners 

Source, image, credits & more information: BemidjiPioneer