What Does Lime Do to Soil? 3 Reasons to Lime Your Garden

In gardening, lime is a rock powder soil amendment made from ground limestone rock, which naturally contains calcium carbonate and magnesium carbonate. The addition of lime to garden soil can increase the alkalinity of acidic soil and add plant nutrients and minerals, creating a healthy lawn and a healthier base for plants to grow.

Agricultural lime and dolomitic lime are two types of lime commonly used in lawns and gardens. Agricultural lime (or garden lime) comes from calcium carbonate, while dolomitic lime comes from dolomite, a type of rock similar to limestone that contains calcium and magnesium. These are not the same as non-agricultural quick lime, slaked lime, or hydrated lime, which have a variety of uses, including cooking and water treatment, but are not for your soil.

The addition of lime to your soil can be the difference between a low yield and a flourishing garden. Here are three benefits to incorporating lime into your lawn care routine:

1. 1. To add nutrients: A low soil pH can inhibit plants from absorbing the available nutrients in the soil, but lime raises the pH level and promotes the spread of good bacteria in the soil by adding nutrients like phosphorus and zinc to it. Keep in mind that if your soil pH is already above 6.5, you will likely want to avoid adding lime since too high of a pH can cause nutrient deficiency symptoms like stunted growth. A high soil pH can also cause chlorosis, which appears as a yellow discoloration on a plant’s leaves.
2. 2. To improve water penetration: When the soil is on the acidic side, adding lime can improve water penetration of the soil. By raising the alkalinity of the soil, water can more easily rehydrate the soil, thereby rehydrating your plants and preventing them from drying out.
3. 3. To make your soil more alkaline: Most vegetables prefer to grow in alkaline soil and adding lime to your soil will increase the alkalinity of the soil. A pH level of 7, which is neutral, works well for most vegetables and flowers, so you might consider increasing the pH level of soil that lands at or below 6.5 when you test it. However, there are some acid-loving plants and vegetables, like potatoes and parsley, so be sure to do some research before deciding to lime your soil.

Testing your soil is the first step in determining when to add lime to your soil since you want to ensure you are applying the right amount. You can test the acidity of your soil yourself with a multi-use soil kit purchased from a local garden center. You should check the pH of the soil in multiple spots in the area where you are planning to plant your vegetable garden to make sure the value you land on is representative of the entire garden.

You can also send a soil sample to local professionals for a pH test to determine your soil’s acidity. The benefit of this step is that they will then be able to explain the soil test results and recommend specifics on how you should be liming your lawn, garden, or flower beds. A soil test will also help you determine the exact amount of lime needed to get your soil to a preferred pH level. Depending on your soil type and the pH reading of your soil, you will need to buy different amounts of lime. For instance, clay soil generally needs more lime than loam soil.

If you’ve found that your lawn or garden is too acidic, you can apply lime to rebalance the soil’s pH level and assist your garden plants in flourishing.

1. 1. Choose fall or spring. Since lime application isn’t a quick fix, it’s best to lime in the fall, at the end of the growing season. By doing this, you allow time for the soil to absorb the lime and for its pH to fully adjust. If you are liming in the fall, you should do so immediately after your last harvest of the season—the results should become evident during the next growing season. If you decide to do your liming in the spring, it’s important to allow as much time as possible for those nutrients to work into the soil before you sow seeds or transplant seedlings.
2. 2. Spread it evenly. You may opt to spread the lime evenly over the top of your soil with a shovel, or you can use an agricultural spreader or fertilizer spreader machine for easy application. When spreading lime, you should wear protective gear, including gloves, a breathing mask, and goggles.
3. 3. Till your garden. Once you’ve spread or broadcasted the lime, you will want to make sure it has mixed well with the soil. Dig down at least 12 inches to incorporate the lime as deeply as your plants’ root systems will eventually grow.
4. 4. Water well. Adding water activates the lime, so water the soil well after you’ve finished liming. A good option can be to use soaker hoses, which effectively and slowly saturate the soil.
5. 5. Wait to sow. If you chose to lime in the spring (at the start of the growing season), wait at least three weeks after tilling before you sow your garden. The additional time will give the lime the opportunity to better distribute. This is one of the reasons many people choose to lime in the fall over the spring.

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