Vegetable gardeners spend a lot of time thinking about conditions that affect successful plant growth, such as rainfall, sun, and temperature. But they often neglect the soil, where plants get the nutrients they need to grow. Soil pH determines the availability of these nutrients; So, for plants to thrive, you need soil with the right pH value for the plants you are growing.
Fortunately, you can change the pH value of your soil, naturally, for healthy plants and a productive garden.
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What are soil pH values?
By nature, soils can be acidic or alkaline. You can determine what type of soil you have by measuring its pH value. There are several ways to test soil pH. For example, you can take a soil sample and send it to a lab for analysis, use a store-bought test kit, or create a do-it-yourself soil pH test.
It’s worth pointing out that the results obtained from a DIY test won’t be as accurate as a lab test, but they will definitely give you clues as to whether your soil is acidic or alkaline. Learn more about soil pH testing methods.
Providing the soil with the correct pH value is the best thing you can do for your plants.
Most soils have a pH value between 3.5 and 10. In regions that receive a lot of rainfall, soil pH values typically range from 5 to 7, while in drier regions, soil pH values range from 5 to 7. pH generally range from 6.5 to 9.
Here is a quick reference for classifying your soil according to pH value:
- 7.6 and above: alkaline
- 6.5 to 7.5: neutral
- 6.5 and less: acid
- Less than 5.5: strongly acidic
According to experts from the University of Nebraska – Lincoln, most vegetables do better with pH or acidity neutral range from 6.5 to 7.
However, some plants grow much better in slightly acidic soil, around 6.1 to 6.5. Why is it so? These plants need higher levels of certain nutrients whose absorption is enhanced by the presence of more acids in the soil. This group includes carrots, cauliflower, celery, cucumbers, garlic, peppers, pumpkins, squash, and tomatoes.
In addition, some plants function more optimally at a pH close to neutrality. These plants include sugar snap peas, kale, lettuce, green beans, cabbage, Brussels sprouts, broccoli, asparagus, and radishes. On the other hand, potatoes do best in significantly more acidic soil, up to a maximum of 6.0.
How to Change Soil pH Naturally
Adding organic matter is one of the best ways to improve vegetable growing conditions, or in this particular case, to adjust soil pH.
Natural amendments are usually added to improve soil structure, as well as to increase organic content and improve moisture retention. Keep in mind that the richer the soil in amendments, the healthier the roots of the plant. In healthy soil with appropriate natural supplements, adjusting the pH level will not be as necessary as plants develop their tolerance to acidic or alkaline conditions.
Raising the pH for a More Alkaline Soil
Adding limestone is one of the most common ways to raise your soil’s pH. Considering that adding limestone is not a quick fix, it is best done in the fall, late in the growing season, well before sowing or transplanting seedlings.
Ideally, you would use a fertilizer spreader to evenly distribute the limescale. But if you don’t have one, you can use a shovel to evenly distribute the lime on top of the soil. Once you’ve spread it, dig up the soil to incorporate the lime as deeply as your plants’ root system will grow. Then water thoroughly. The amount of limestone you use depends on your soil’s needs, but below are some rough numbers.
- Sandy soil needs about 2 pounds of limestone per 100 square feet.
- Loamy soil needs about 3.5 pounds of limestone per 100 square feet.
- Clay soil needs about 5 pounds of limestone per 100 square feet.
Learn more about applying limestone.
2. Wood ashes
Using wood ash is one of the easiest ways to naturally alter soil pH, but it is not sustainable. Simply spread about ¼ inch of wood ash evenly over the surface of the soil to be treated, preferably on moist soil so the wind does not blow it away. Then use a tiller, spade or rake to push it into the ground. Avoid using chemically treated wood ash at all costs to avoid contaminating your soil.
3. Baking soda
Using baking soda is a cheap, quick, and easy method to raise your soil’s pH. All you have to do is mix a tablespoon of baking soda in a gallon of water and water your plants thoroughly. You will get the best results if you repeat the procedure every few months.
Lower the pH for a more acidic soil
1. Elemental sulfur
Did you know that soil bacteria convert sulfur into sulfuric acid, which lowers soil pH? It is very important to point out that sulfur can even increase the resistance of plants to diseases.
For best results, apply before planting and then to a depth of 6 inches. This speeds up the pH adjustment. However, if you are applying it to soil where you have already planted, you will need to add elemental sulfur bit by bit as much as possible. Rake gently to mix it into the soil without disturbing the plants.
For example, if you want to plant blueberries that need a pH of up to 5.5 but your soil pH is 7.4, feel free to use about 1 1/3 to 2 lbs. . (2 3/4 to 4 cups) of elemental sulfur per plant. It is important to do this a month before planting to avoid burning the roots.
If the plant is already established, use 1/6 lb (1/3 cup) of elemental sulfur per plant and repeat the process for the next month until desired levels are achieved.
2. Peat moss
Peat moss is an excellent soil amendment for acid-loving plants and can also help retain moisture in the soil. Note that the action is quite slow and may not be effective in causing significant changes in soil pH. If you go this route, we recommend adding a 1-2 inch layer of peat moss and incorporating it into the top 6-12 inches of soil before planting. Unfortunately, peat moss harvesting destroys environmentally beneficial wetlands and releases CO2, a major contributor to climate change. Thus, we recommend alternative solutions to lower soil pH.
To lower soil pH with vinegar, you must create a diluted vinegar solution. Mix 1 cup of vinegar to 1 gallon of water and water your plants using a watering can or squirt it into your irrigation system. That’s quite enough to start with, test the soil regularly and if you see no change or the changes are very small, feel free to use one of the methods mentioned before.
Gardening starts with the soil
It is well known that gardening success starts with the soil; it is the basis of your whole garden. Therefore, the proper pH value is of great importance as it determines the availability of almost all essential plant nutrients.
No healthy and productive plants without quality and balanced soil. This is where natural amendments, which have the ability to improve the overall condition of the soil and deliver nutrients directly to your plants, come to the rescue.
Finally, don’t be discouraged if everything doesn’t work the first time. Although it may take some time to figure out exactly which actions will produce the best results, it is possible to make the most of the garden soil you have.
About the Author
Tony Manhart is the founder and editor of Gardening Dream. Tony’s enthusiasm and wealth of experience in all things plant growing has led him to share his knowledge with gardening enthusiasts around the world. When he’s not working in his garden, Tony spends his time writing tips and tricks on various topics related to plant growing and soil care.