We use soil tests to tell us how to create soil that has a natural ability to fight issues. If you have weeds, this is a sign your soil is out of balance with an incorrect pH and is deficient of sufficient levels of microorganisms. In other words, weeds show symptoms. Nature grows weeds to prevent erosion and to provide nutrients to soil where it is deficient.
Proper pH is absolutely necessary for lawns to be resistant to weeds, drought, disease and insects. Turf grass naturally fights these issues when the soil pH is 6.5-7. Soil pH is a scale from 0 to 14 that measures acidity and alkalinity, with a low number being acidic. Lime is added to “sweeten” and make soil less acidic. Sulfur is added to make the soil more acidic.
Without the proper pH level, nutrients are either trapped in the soil or they leach out too readily. Even though pH tests purchased at lawn centers give us a reading, they do not tell us the volume of product to add to the soil. On the other hand, a soil lab test tells us exactly what to add and how much of it based on your soil’s texture and percentage of organic matter.
Organic matter makes up the smallest portion of the soil profile (about 6-7%), but it is where all of the action takes place. Nature has put microorganisms in the soil to help us grow things. Soil rich in microorganisms contains thousands of different organisms competing for survival (where one organism consumes another) and the chance to reproduce. Food for your lawn, in the form of gases and by-products, is slowly released as they consume each other.
Compost top dressing is a great way to give the microorganisms an organic food source. Their digestion converts the food into carbon dioxide, nitrogen, and other essential elements that the grass can then use to grow.
Soil testing is used as a baseline and a way to benchmark progress. A soil test reveals:
• Organic matter content (optimum range 5-8%)
• Calcium to magnesium ratio (optimum ratio 10:1)
• Micronutrients sulfur, calcium, magnesium, zinc, iron, manganese
• Amount and type of lime to use
• Levels of macronutrients NPK—Nitrogen, phosphorous, Potassium
• Transition steps from a synthetic to organic lawn
Perform tests annually until soil is working well on its own and nothing needs to be added. The best time for a soil test is the fall, long after applications have been applied. If doing one in the spring, perform it before doing any applications. Also, avoid performing a test after it has rained or watering has just happened.
Nature grows weeds to provide nutrients to soil. For example, clover is a nitrogen fixer. Clover extracts nitrogen from the atmosphere and puts it back into the soil. It appears in areas where nitrogen levels in soil are low.