Testing Soil pH - How to Test Your Garden Soil pH Level
How to test your soil, and how to change the pH level
Testing soil pH (periodically) will help ensure that you're getting the healthiest and biggest yield of crops from your garden. Testing soil pH every three years is optimal in providing your plants an environment in which they are healthy and continue to produce high yields.
pH – How can two little letters (ok, one little letter and one big) be so important to a garden’s success? Everything (soil, food, even a person) has a pH level. pH is a measurement of how acidic an entity is. Conducting a soil pH test is the best way to find out how acidic your soil is.
Different types of plants have different requriements for their optimal pH level. For example, tomato plants prefer a soil pH level that's between 5.5 and 7.5. Lettuce prefers a pH between 6.0 and 7.0, but won't tolerate a pH over 7. By testing soil pH in each garden bed, you'll have the opportunity to provide your garden it's best opportunity for having successful growing conditions.
Placing plants in garden soil that does not match their pH needs can weaken the plants by:
- Making them more succeptible to plant diseases and insect infestations
- Causing the plant to grow more slowly and have a smaller yield
- Reducing the amount of nutrients being passed from the soil to your fruit, herbs or vegetables
Most plants will grow well in soils that test within a pH level in the range of 6.5 to 7.0. For information on individual plant pH level soil preferences, you can look up your favorite plants here (check under the "How to Prepare the Garden Soil" subheading for the plant's pH level requirement):
Gardening Tip: Testing soil pH will quickly tell you what your garden plot's pH level is. However, keep in mind that the pH level of one area in your yard may not be the same as another. Gardening plots that have been worked more with organic matter or mulched over the years may read differently than a brand new garden bed.
Testing Soil pH- How to Test Your Garden's pH Level
Option 1: purchase a pH soil testing kit from any garden supply store (they are simple to use and inexpensive), and follow the instructions provided.
Normally, your pH soil testing kit will have a container, a testing solution, and a color chart. To conduct your soil test, the process is generally that you scoop up some garden soil and place it in the container. Add the recommended number of drops (of testing chemicals) to the container. Mix (shake) the container for the time recommended on the package's instructions. Compare the resulting color to the chart provided and pick the best match to identify your garden plot's soil pH level.
Option 2: take a sample to the local county or university extension office's soil testing facility. They will often test your soil for you (with a more in-depth test) for a minimal fee.
Reading your pH Level Results
The results of your soil test will show a pH level for your garden plot, measured on a scale of 1 to 14.
1 = the highest acidity and the lowest alkalinity
14 = the highest alkalinity and the lowest acidity
A reading of 7 is considered neutral soil. Below 7 is considered acidic soil (the opposite of alkaline). Likewise, a reading of above 7 means that you have alkaline soil (the opposite of acidic).
While at first, the difference in the results of your reading may seem insignificant, the reality is that the slightest reading change can have a big impact on your soil's productivity. On the scale, each whole number is 10 x the acidity/alkalinity of the neighboring number. For example, a reading of 6 is 10 times more acidic than a 7. A 5 is 10 times more acidic than a 6, and 100 times more acidic than a 7.
Note: You may also want to test your water's pH level. Deep wells can often be alkaline, and thus watering with them will help lower your soil's acidity. City water varies in pH, so it's a good idea to test it also.
Some plants prefer acidic soil, some prefer neutral soil, and some prefer alkaline soil.
Gardening Advice Tip: Don't forget to do a soil test for the pH for the plants in your container garden, or your house plants!
Changing Your Garden Plot's Soil pH Level
The absolute best additive for your soil (whether too alkaline, or too acidic) is well-rotted organic matter, like compost. Compost acts as a neutralizer in both circumstances, and provides the additional benefit of adding nutrients to your soil (for your plants, and also for the fruits and vegetables you plan to eat from them).
Changing Alkaline Soil:
How to change the soil pH level to a lower reading
(the pH level reading is too high)
If your soil test shows that the garden bed is too alkaline (the pH level is too high) for the plants you wish to grow there, you will need to add compost or other organic matter. Soils that are highly alkaline, tend to have significantly fewer nutrients available in the soils. Adding significant amounts of organic matter to your garden bed will help correct this deficiency.
For more information see:
What to use to reduce soil pH
Changing Acidic Soil:
How to change the soil pH level to a higher reading
(the pH level reading is too low)
If your soil test shows that your garden bed is not alkaline enough (in other words, that your soil's pH level is too low (ie. too acidic) for the plants you wish to grow there, you will need to raise the pH level of your garden plot's soil.
Common options available for soil additives that will increase the soil's pH level (reduce acidity):
Apply the soil additive to your soil and rake it in to the top level of soil in your garden plot. (The majority of your plants roots will be near the top, so this is where they will be feeding most heavily from the soil).
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Note: the advice and information contained herein is based upon our experience and study. As with any advice, please apply at your own discretion.