by The Long Island Gardener

Created on: April 12, 2008   Last Updated: December 06, 2011

Liming is everything, insist lawn care pundits. Lime your soil in the Spring, they warn. Grass won't grow in acid soil! Raise pH! Lime, lime, lime all the time, time, time.

True, some soils improve when you treat with lime. But it's not true that ALL soils need these treatments.

In fact, putting lime on your lawn might be a big mistake. Those capricious twists of lime could be all it takes to set off an Iron, Manganese or Zinc shortage in your soil, according to turfgrass experts coast to coast. Never ask "When?" before you ask "If?" you should lime your lawn.

The Acid Test

Fact is, almost all lawn grasses grow best in slightly acid - not alkaline - soil  The non-profit Turfgrass Producers Int'l points out that most lawns perform best in soil pH between 6.0 and 7.0.

The Northeast's most popular turfgrass, Kentucky Bluegrass, prefers a pH of 5.8-6.5. That's below the 7.0 pH "neutral" cut-off - acid soil. Tall Fescue seconds that. Creeping Bentgrass is Bentgrass thrives in soil measuring between 5.5 and 6.5.

Still skeptical? Check the charts: Most lawns are quite content with solidly "sour" soil - the old farmer's vernacular for dirt with a low pH, detected by taste.

Zoysia likes its soil pH around 5.5. Warm Season Carpetgrass likes a spicy 5.0 pH. Not a single turfgrass thrives ONLY in alkaline soil - pH levels higher than 7.0. Many merely languish in it, because soil pH determines nutrient availability.

Too much lime actually traps plant nutrients in soil particles, locking them out of reach of your lawn. Your grass turns yellow when you over-lime your soil.

Time to Lime? 

How do you know it's time to add lime to the soil?

Back in the old days, farmers would taste it. Soil that tasted like Vinegar was "sour". Only then did a farmer know it was right to lime. "Sweet" soil needed no lime.

Today, you can order a soil test and have a complete analysis, pH included, from your local Cooperative Extension. Or you can pick up a quick soil testing kit at your neighborhood garden center. New construction is almost always surrounded by soil with chunks of cement, which raises pH and may not need lime. Soil with pine needles and evergreens dotting the natural landscape is almost certainly acidic, and needs a good dose of lime.

Still, Experts caution against lime unless the pH is 5.4 or lower. Think your soil is acid?

It's still not lime-time for certain. Test it to be sure.

A final word of warning: If you do need to raise the pH, be patient. It takes years for lime to work. This element does not move itself through soil. Established lawns need annual spring surface treatments.

Sweet? Sour? Taste it.  Test it.  Whatever you do, make absolutely sure you need it first, or you may do more harm than good.

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