7 Natural Ways to Make Soil More Alkaline

Maintaining optimal pH levels is essential for plant health and growth. Alkaline soil (pH above 7) benefits certain types of plants.

Boosting soil alkalinity can help certain plants grow better and improve yields when the soil is too acidic for their needs. This article will explore natural ways to raise your soil’s pH and make it more alkaline.

Things to Consider Before Adjusting Soil pH

Most garden plants grow best in slightly acidic to neutral soil with a pH between 6.0 and 7.0. Therefore, avoid drastic changes unless your soil is well outside your plants’ preferred range.

Adjusting soil pH too much can reduce nutrient availability and harm plant growth.

Factors to consider before making changes:

• Plant type: Know your plants’ pH preferences.
• Soil type: Sandy soils respond to pH changes faster than clay soils [1].
• Current soil pH: Testing your soil’s pH is key. It helps you know what adjustments to make.

Soil pH Testing

To test your soil’s pH at home, use a pH test kit available at garden centers or a simple DIY method.

DIY Vinegar and Baking Soda Test:

First, collect soil samples from different areas of your garden. Next, place about one tablespoon of soil into a small container.

Finally, add a few drops of vinegar. If the soil fizzes, it’s alkaline.

If there’s no reaction, add a small amount of water to another sample. Next, sprinkle baking soda over it. If it fizzes, the soil is acidic.

This DIY test provides only a rough estimate of soil pH and is less accurate than a soil test kit or a digital meter.

How to Make Soil More Alkaline Naturally

Soil pH changes gradually over time. Therefore, it is best to make adjustments slowly and retest the soil periodically instead of trying to raise the pH too quickly.

Let’s explore some natural ways to raise soil alkalinity.

1. Wood Ashes

Wood ashes are a natural way to raise soil pH. They contain potassium, calcium, and magnesium, which are alkaline-forming nutrients.

To apply, first collect ashes from a clean wood-burning source. Avoid ashes from treated or painted wood [2].

Once cooled, spread a light dusting or thin layer of ash over the soil surface. Work the ashes into the topsoil gently.

Since wood ash is high in calcium, potassium, and other alkaline minerals, it raises the soil’s pH. However, over-application can cause pH levels to spike too high, potentially harming plants.

Therefore, gradually apply ash and regularly test your soil’s pH to monitor its effects.

2. Agricultural Lime

Agricultural lime (also called garden lime) is one of the most common and effective remedies to make soil more alkaline.

First, determine the current pH of your soil and the type of soil you are working with. This way, you will know how much lime to apply.

Clay soils require more lime to raise the pH than sandy soils do.

Now spread the lime evenly across your soil surface using a broadcast spreader or by hand for smaller areas. Next, work the lime into the top few inches of soil using a rake or tiller for better absorption.

Lime works gradually, so it may take several months to see the full effect [3].

3. Baking Soda

Baking soda is another household item that can help raise soil pH. However, it is best used in small, contained areas (such as pots or small garden beds).

Mix about one tablespoon of baking soda into one gallon of water. Stir the solution until the baking soda dissolves completely.

Then, use this mixture to water the soil around your plants, applying it evenly to the areas where you want to raise the pH.

However, avoid frequent use, as baking soda contains sodium, which can accumulate in soil and damage plants over time.

4. Oyster Shell Lime

Oyster shell lime is primarily made from crushed oyster shells rich in calcium carbonate.

It’s slower-acting, meaning it gradually helps neutralize soil acidity. Therefore, it is a gentler option compared to other remedies.

Since oyster shell lime works over time, regular soil pH testing will help track progress and prevent overapplication.

5. Eggshells

Pulverized eggshells are also a great way to add calcium to the soil and raise pH over time.

To use, start by collecting and thoroughly cleaning the shells to remove any residue.

Once dry, crush the eggshells into a fine powder or small pieces. The finer the texture, the faster they will break down in the soil.

Next, sprinkle the pulverized eggshells evenly around the base of your plants, or mix them directly into the top layer of soil.

Powdered eggshells may contribute to a gradual increase in soil pH over time as they slowly decompose. They are a gentle, natural choice for raising alkalinity.

Eggshells break down very slowly, so they are best for gradual, long-term pH adjustment rather than quick changes.

6. Bone Meal

Bone meal may have a very slight effect on soil pH over time, but its main value is adding phosphorus and calcium.

To apply, sprinkle it evenly over the soil surface or mix it into the soil at planting time.

However, be sure to follow the recommended dosage on the packaging. Also, periodically monitor your soil’s pH to assess the effects and avoid overapplication.

7. Dolomitic Lime

Dolomitic lime is a type of agricultural lime that contains magnesium in addition to calcium. It is an excellent choice for soils that are both acidic and magnesium-deficient.

To use, begin by determining your soil’s pH and magnesium levels. Next, spread the lime evenly across your soil surface using a broadcast spreader for larger areas or by hand for smaller patches.

Work the lime into the top few inches of soil to ensure it is well mixed. Dolomitic lime also works gradually, so it can take several months for the soil’s pH to adjust fully.

Plants That Prefer Alkaline Soil

Several plants grow well in alkaline soil, including lavender, carnations, and lilacs. Some clematis varieties also tolerate alkaline conditions.

Certain types of vegetables, such as beans, cabbage, kale, and beets, also thrive in alkaline soil.

Takeaway

Raising soil pH can take time and effort, but it can also be a rewarding process that helps plants that tolerate alkaline soil thrive.

Regularly check your soil’s pH. Natural amendments such as agricultural lime, wood ash, and crushed eggshells can gradually raise soil pH when used carefully.