Fertilizer & NutritionSoils & Grow Mediums

Why It is Important to Test and Know Your Soil

You’ve likely heard something along the lines of, “Good soil makes good crops” if you’ve been gardening for any amount of time, but do you know what makes quality soil? And if you do understand what goes into good soil, do you know how to check if your soil measures up?

What is NPK?/What does NPK Stand For?

NPK is an initialism that stands for nitrogen, phosphorus, and potassium. These are the big three nutrients that are necessary for healthy soil. An excess or deficit of any of these three nutrients will result in improperly developed plants. At best, you’ll get reduced or inedible yields. At worst, all of your plants will die off.

Each nutrient corresponds to a specific aspect of how plants develop.

Nitrogen is commonly equated with the amount of “green” in one’s garden. Too little nitrogen will cause yellowing in leaves and stunted growth in the plant. Too much nitrogen will cause an excess of blooming, which quickly results in rot. Additionally, over-applying nitrogen will result in the excess nitrogen being washed away during rainfall. As this runoff flows into streams, ponds, and other bodies of water, it becomes extremely harmful to the environment.

See ARBICO’s nitrogen solutions here

Phosphorus plays a critical component in plant growth and development. A lack of phosphorus results in stunted, shallow roots, and spindly stems. A plant’s reproductive capabilities will also be inhibited if a plant has a phosphorus deficit. Phosphorus levels require proactive monitoring. By the time you notice the physical signs of a phosphorus deficit, it’s usually too late to save the plant.

See ARBICO’s phosphorus solutions here.

Potassium benefits plant health and root strength. Proper potassium levels in the soil make crops more resistant to disease. Generally, proper phosphorus levels don’t need to be as high as the levels of nitrogen and phosphorus in your soil. If you’re growing plants that produce fruit, maintaining proper potassium levels can result in firmer and more flavorful fruit.

See ARBICO’s potassium solutions here.

What about Soil pH?

Just like how each species of plant prefers different amounts of water and different temperatures, the preferred soil pH varies between plants. A perfectly neutral pH isn’t always the best. Typically, most plants do best when the soil is slightly acidic and between 6 and 6.5, though there are exceptions to this rule of thumb. For instance, blueberries do best when the soil has a distinctly acidic pH of 4.5, while asparagus actually needs a pH of 7 or slightly higher. Make sure that you check the pH of your soil before planting new seeds and continue to check it while planting to ensure that no imbalances have unexpectedly occurred.

Anything Else?

Nitrogen, Phosphorus, and Potassium aren’t the only nutrients necessary for healthy soil. Other trace elements play important roles in soil and plant health.

Calcium keeps roots healthy and encourages the growth of root hairs, which are critical for absorbing water from the soil. Magnesium is a critical component in photosynthesis and keeping the chloroplasts in plant cells functional. Sulfur maintains the integrity of amino acid chains and helps with nitrogen intake.

The Basic Needs of Soil

In addition to nitrogen, phosphorus, potassium, a proper pH level, and numerous trace elements, there are other aspects to healthy soil. The presence of organic matter is a critical part of healthy soil. Organic matter is composed of three categories: living, dead, and very dead. Living organic matter are creatures that live in the soil, such as earthworms and smaller microorganisms. Dead organic matter can range from fallen leaves to deceased organisms to manure. Very dead organic matter is also referred to as soil humus, and it is largely insulated from chemical change. Adding compost to your garden is a common way to maintain proper levels of organic matter in a controlled growing environment.

How to Test Soil

For an easy to use pH and NPK tester, try the Luster Leaf® Rapitest Soil Test Kit. Just take a sample of the soil 2-3 inches below the surface then mix with water. Transfer the soil-water mix to the test chamber, then add the powder from the appropriate capsule (pH, Nitrogen, Phosphorus, or Potassium). The mixture will change color—just match the color to the included guide to determine the pH or NPK level.

From soil testing and replenishment to pest control to organic fertilizers, ARBICO Organics has been providing solutions to both professional and hobby growers since 1979. Check out their full catalog at Arbico-Organics.com.

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