‘Sweeten’ Your Lawn And Garden With Lime

Did you know that you can add tons of fertilizer to your garden and lawn, and it can do absolutely nothing, nada?

You can take all the time, make all the effort, and it’s all wasted. This is because you never had your lawn or garden soil tested for its pH level, and if you don’t know your soil’s pH you can’t possibly know how much lime you need to adjust it.

In very simple terms, if your soil pH is off, many nutrients simply don’t become available to the plants. Too little or too much lime (used to “sweeten,” or adjust, the pH) can also be as disastrous as none at all. But adding just enough lime to bring your pH into balance can make a world of difference. It can allow your lawn to green up and stay healthy. It can allow your vegetables and fruits (blueberries like very acid soil but raspberries prefer a more neutral soil) to taste as good as you imagined they should. But remember that rhodies and azaleas like their soil on the acid side.

Technically speaking, soil pH or soil reaction is an indication of acidity or alkalinity of soil and is measured in pH units. The pH scale goes from 0 to 14, with 7 being the neutral point. Lower numbers indicate acidity while higher numbers show alkalinity. Our soils on the East End are known to be on the slightly acid side, but there are two factors that add to the acidity. One is acid rain. The second is fertilizer. Many fertilizers contain acids and over the years the continuing addition of fertilizers to lawns and gardens can have a cumulative effect, making the soils more and more acidic.

There are more than a dozen nutrients, micro and trace elements that become unavailable to plants in your lawn, garden and entire landscape when the pH goes out of whack. Limestone, or calcium, however, when properly added, can be nothing short of a miracle.

Lime is not necessary for all plants in all soils. Contrary to popular belief, it is not a fertilizer, but it does have an active role to play in your garden and lawn. Lime is usually calcium carbonate, and if you don’t know it yet, plants must have calcium in order to grow properly. In soils made up from primarily limestone rocks there is no lime deficiency, but in our acid soil you’ll commonly see landscapers and farmers adding lime to “sweeten” the soil.

A “sour” soil is one with most of the lime leached out. In areas where soils are derived from acid-bearing rocks the calcium is easily leached out, and this is where you’ll see farmers adding truckload after truckload of limestone. You may need to do the same thing but on a smaller scale. A good indicator (prior to a soil test) that you may need lime is a green scum or spotty moss where grass should be growing, but these are clues, not answers, and they need not be visible for a problem to be present.

We also know that there are pockets of clay throughout the local villages and green belts. Lime added to these soils not only adjusts the pH, but it also changes the physical condition of the soil, making it more workable. It causes the finer particles of clay and silt to combine, forming larger particles. The result is the formation of spaces that allow for the movement of air and water.

There are several types of lime on the market, and your choices will depend on your budget, the time you can take to apply the lime and how strong your back is. A few decades ago, we had no choices and simply applied ground limestone in a powdery form. The stuff was dirty to work with and, if applied with the slightest wind, it would drift everywhere but down to the ground. Ground dolomitic limestone is still an alternative especially if your soil test shows a magnesium deficiency (use calcitic lime for calcium deficient soils), but these days we use pelletized lime and other products that are virtually dust-free and easy to apply with a rotary spreader. Lime actually needs to be in a powder form to work and the pellets simply break down and turn into the powder form. Keep in mind though that it may take up to six months to see changes in your pH from granular, pulverized or pelletized lime, but there is a faster alternative.

One thing to remember, though, is that it takes limestone a long time to break down and become active in the soil. This is why we usually apply late in the fall as the freezing and thawing during the winter months work the lime into the soil, aiding in its becoming useful. But even then the process is slow, and you may not see any change in the soil pH for a year or more.

There is also a product called Solu-Cal (solu-cal.com) that works very differently. It will change your soil pH in a matter of weeks and will continue to work for a number of months as a result of the way that it’s formulated. You also need to use less of it than the other products so a bag can go much farther than a bag of pelleted lime. Another plus is that it can be applied virtually any time the year, and you get fast results. On the downside, a bag of Solu-Cal may cost four times as much as pelletized lime. The true cost, however, is much less since you use less of the product. Solu-Cal is widely available, and you can find it in the East End garden centers.

If for some reason your lawn is extremely fine, has lots of bentgrass in it and you like to keep it cut very short, then another type of lime that is a micro prill is for you. The particles are tiny and uniform and don’t interfere with close cutting. Lastly, there is a soluble or flowable lime. This is usually used as a last resort on golf courses or high-end landscaping because of the prohibitive cost, probably in the thousands-of-dollars-per-acre category.

For your vegetable and flower gardens, there’s no reason not to go the with pelletized lime as you may need only a single bag. But even here there are alternatives, kind of. Oyster shells (ground up, of course) are an excellent source of calcium, but you’ll need to truck them home and then find a way to grind them. Some local garden centers may be able to get them for you also.

A soil test, which I’ve been after you to take care of for years, will tell you how much lime you need, but there are old stand-by rules. In the absence of a soil test, the rule of thumb is a ton of lime per acre every two to five years. If you are fertilizing with chemical fertilizers (which are very acidic) you’ll need to be on the more frequent end. On the other hand, if you use organic fertilizers, you’ll do it less often. In any event, over liming can cause problems as well — so get a soil pH test every couple of years and let that be your guide. If you want to play it safe, you can apply limestone every fall in a maintenance program. In this case, you’ll apply only 5 to 10 pounds per 1,000 square feet and your soil should be forever sweet.

The best bet, though, is with a soil test. Many local garden centers will test your soil samples for pH and they sell inexpensive kits that allow you to do quick tests at home. These tests are not as accurate as tests done by a lab or through the Cooperative Extension office in Riverhead (631-727-7250 extension 335), but they can give you a good guide. Some home testing kits also come with guides that let you translate the test results into the number of pounds of lime you need to add per 100 or 1,000 square feet. Remember though, some plants like rhodies and azaleas prefer a slightly acid soil and adding lime in rhodie or azalea beds may give unwanted results. Keep in mind also that the pH in your vegetable garden soil, your blueberry patch and your lawn may differ. Keep growing.