Q: Why is soil pH so important?
A: The pH is most important factor in growing grass since it affects the availability of nutrients in the soil that are essential for plant growth. Optimum range soil pH should be for grass is 6 – 6.6 on the pH scale. Depending on how acidic soil is, grass may not even be receiving nutrients from the fertilizer. Other than the pesticides that are sometimes included with fertilizer, some may just be wasting their money fertilizing if they have acidic soil! This is why having the soil tested is extremely important. Once at optimum level; the next time you seed you will have better results, grass will thrive and be more durable. Even weed controls will work better!
If your soil is too acidic, lime is recommended. Sometimes multiple applications are recommended when soil is very acidic. Please keep in mind, each lime application may take 6 months to fully correct the soil pH and 50 pounds per 1,000 square feet is the most that can go down at one time without wasting. If indeed multiple applications of lime are needed, they would have to be spaced out 6 months apart to efficiently correct the soil pH. Lime can be done anytime of the year and will not burn grass if incorrectly applied. Can you apply too much lime? Yes, if the soil was already neutral or alkaline and lime was applied on a regular basis. Over applying one application would just waste money. So don’t assume a heavy dose of lime is needed annually and have soil tested!
Micro-nutrients included in lime:
This usually goes hand in hand with soil pH, but not always. Calcium plays a major role in the physiology of grass, strengthening its physical structure, increasing nutrient uptake and protecting grass from disease.
If this nutrient is needed, dolomitic limestone would be applied instead of your usual calcitic lime. Dolomitic lime contains calcium, but higher levels of Magnesium. Magnesium is a carrier of phosphorus in plants, regulates the absorption of calcium and plays a major role in photosynthesis.
Learn about soil testing, please visit Rutgers Soil Testing Laboratory.