Soil pH test is a standard measure of soil acidity or alkalinity. The measurement of acid soil or alkaline soil will help you decide if your garden is appropriate to grow certain plants. Some plants grow well in acidic soils while others may require neutral or alkaline-based soils. To determine what your soil can yield; you must start with testing it with an appropriate measurement.
Soil pH is the appropriate measurement to test the concentration of Hydrogen ions in the soil. You can test the hydrogen ions level through different mediums but getting a reliable reading is essential to determine the exact proportion of acidity and alkalinity in soils.
Please ask why? Well, because the soil’s conditions greatly determine the growth of plant roots, stem, strip, and flowers. You’d figure what nutrients your soil is lacking only after doing the test. This will also help you determine what kind of soil amendment or fertilization you’d need to utilize to get the soil back in an appropriate condition.
Things to Know Before Doing the Soil pH Test
Before looking into soil pH testing methods, let’s talk about more different determinants of Soil pH, such as how different types of nutrients react to the soil condition and how does soil pH determines the mobility of nutrients.
Effects of Soil pH
The scale of soil pH goes from 0 to 14 where pH 7 indicates a neutral point. It is a ‘reverse’ scale, i.e. soil with acids or organic acid has a low pH and a high hydrogen ion concentration. Therefore, at high alkaline pH values, the hydrogen ions concentration is low.
Soil pH mainly affects the number of nutrients and chemicals that are soluble in soil water, and there is the number of nutrients available for plant growth.
How Does it Affect Plant Nutrients?
Plants may need different kinds of nutrients to grow in their natural form. Three of these major nutrients are Nitrogen, Phosphorus, and Potassium, which are measured in the NPK scale that you can find in almost every fertilizer label.
Soil pH helps determine if these nutrients are readily available in soils. The type of plant will determine what nutrients it needs more in amount, so after doing the soil pH test you can start amending the soil for the plant.
The Mobility of Nutrients
The nutrients can only be supplied through basic soil and water. Hence, the state of your garden soil pH will greatly determine if these nutrients will easily react with soil microbial activity and if your plants will be able to retain them through the soil.
The mobility of essential minerals elements in acidic soil compared to alkaline strongly differs. Nitrogen and Potassium are water-soluble and are mobile in the soil while phosphorus rather remains immobile. To fix this, you’d need soil amendments to reduce the acidity of the soil.
Likewise, some plants would struggle to grow in the alkaline soil, for that you’d need to decrease the level of alkaline and bring it to neutral.
How to Alter Soil pH Level?
The soil that witnesses a lot of fertilization and irrigation will keep changing its pH level. The soil becomes more acidic after continuous fertilization. It retains more nitrogen and sulfuric acid in the soil particles and decreased the soil pH level. Many essential nutrients may be taken up ineffectively at a low pH level causing a nutrient deficiency.
Before you can start with planting, you’d need soil amendments with appropriate chemical agents. Soil pH can be reduced most effectively by adding elemental sulfur, aluminum sulfate, or sulfuric acid.
You can rely on organic matters and lab chemicals to alter the soil pH level. Two of the most common chemical agents used for altering soil pH levels are ground limestone, calcium carbonate, or dolomite line, and common sulfur.
Natural agents like liming materials and dolomite lime can help to increase the pH level of the soil. Finely Ground sulfur and its variants like ferrous sulfate, ammonium sulfate, and aluminum sulfate are great in lowering the soil pH level. You can also rely on organic matter to help lower the soil pH over time by regularly applying compost and manure.
Soil pH Test
Knowing that your soil is probably alkaline or acidic isn’t enough. Experts suggest taking soil tests on a regular basis to understand if you’d need fertilization.
Although there are various ways to test soil pH, the most reliable way is to use certified testing kits.
You can test your soil at home with three different types of soil pH testers: chemical-colored dyes, pH test strips, and electronic pH meters.
Chemical Colored Dyes
Chemical colored dyes are combined with the soil-water mixture. The reading is obtained through the resulting color. You would need to see the kit’s accompanying chart to determine the pH level. However, this kind of test often produces inaccurate results.
pH Test Strips
pH Test Strips are an advanced version of litmus paper but they are more accurate than litmus paper. pH test strips contain several color spots and the accuracy will depend on the range they cover. A large number of color spots produce better accuracy in the result. pH test strips are more accurate than chemical-colored dyes.
Electronic Soil pH Meters
Electronic soil pH Meters are garden-quality tools to measure the accurate reading of soil pH. All you’d need to do is insert the probe attached to the meter inside the soil sample and read the testing.
Soil pH Meter
A soil pH Meter is a type of electronic pH meter that reads the soil pH with the help of a voltmeter. Fundamentally, a soil pH meter consists of a voltmeter attached to a pH-responsive electrode and a reference (unvarying) electrode. When the two electrodes are immersed in a solution, they act like a battery that produces electric potential (charge) that can be read in the meter.
Soil pH Meter can be used indefinitely, requiring only occasional calibration.
- Take three or four samples, two to six inches deep. Try taking soil samples from different sites of the garden soil. Remove twigs and stones.
- Put the sample inside a bottle and mix it with water. It’s important to use water that is neutral-pH such as distilled water but tap water. Now, insert the test probe and wait about a minute. You should get a reading.
- If the pH registers as being lower than 7 that means your soil acidity is higher. Higher than 7? Your soil is alkaline. (Exactly 7 means your soil is neutral.)
DIY Soil Testing Methods
The DIY methods recommended by the soil testing lab work well when you don’t readily have a soil test kit at home. However, they provide very inaccurate results, so you should only use them for referential purposes.
The Red Cabbage Method
- Chop the cabbage into small pieces before boiling it in a pot of distilled water. Boil it for 10 minutes; you’d see violet-colored water. Remove the pot and strain out the cabbage.
- Then, pour some of the water from the pot into a clear container. Add a spoonful of soil sample into the water and see how tic changes color. If the water turns pink, your soil acidity is greater. If it turns blue-green, is it alkaline?
The Vinegar/Baking Soda Method
- Dig and collect soil samples from different sites. Be sure to remove twigs and stones. Next, place the soil solution into a clean glass container and add enough distilled water to turn it into the mud. Then add a cup of vinegar to it and stir slightly. If the soil fizzes, foams, or bubbles, your soil is alkaline.
- If nothing happens, you can continue the same process with a different sample and then add ½ cup baking soda into the solution and stir it slightly. If the soil fizzes, foams, or bubbles, your soil is acidic.
Are Soil pH Tests Accurate?
The accurate readings of pH meters generally range from ±0.1 pH to ±0.001 pH. For instance, a pH meter with an accuracy of ±0.01 is a good choice for quality control or research environments; however, a pH meter with an accuracy of ±0.10 may be more affordable for a school laboratory and be adequate for their needs.
Experts suggest staying away from less expensive meters because they can be off by as much as 1.5 points. Accurate models generally cost $50 to $70
For the soil pH tests to be accurate, you have you start with properly calibrating your pH meter. You calibrate a pH meter by dipping it into buffers (test solutions of known pH) and adjust the meter accordingly. Some meters have built-in thermometers that can automatically correct their own pH measurements as the temperature of the soil-mixture changes.
Don’t forget to use distilled water to make soil-water the mixture before using your pH Meter.
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