Test Your Garden Soil for pH Balance
As the winter weather subsides, my thoughts turn to planting spring crops in the vegetable garden. Though I live in the southwest desert, and the growing season is nearly year round, the winter rains and occasional frosts change the pH balance of my garden soil. Come springtime, I turn the soil in the garden beds and using an inexpensive soil pH meter purchased from the local garden center, I test the soil in each bed for pH balance.
Why pH Balance is Important
A pH balance describes the acidic or alkaline level of a substance on a scale of 0 to 14, with 7 being neutral. A pH balance less than 7 is acidic. A balance higher than 7 indicates the substance is alkaline. Lemon juice, for example, has a pH balance of 2, while ammonia has a pH balance of 11.
Plants take up nutrients from the soil through their root systems. The roots can only absorb the nutrients if the pH of the soil "matches" that of a plant's ability to take up nutrients.
The pH balance directly affects the solubility or chemical state of nutrients. If the nutrients aren't in a matching state of solubility to a plant's needs, the plant roots are unable to absorb the nutrients in the soil. For the roots of most vegetable plants to absorb nutrients, a pH balance of between 6 and 6.9 is optimal, or a slightly acidic soil.
How to Test for pH Balance
Water the garden to moisten the soil the night befire the test. The water also has a pH balance, and the effect it has on the soil provides an accurate reading of the garden soil when it's moist.
Choose one area or bed in the garden to start the testing. Dig down into the soil 4 to 6 inches and turn the soil to loosen.
Following the manufacturer's instructions, insert the probe of the pH meter into the soil and wait approximately 60 seconds. The reading on the meter is the pH balance of the soil in that bed.
Write the pH balance on a plastic row marker and insert it into the soil where you took the reading. Repeat the test throughout the garden, testing each bed or area, and marking them with the results.
What to Do About the Results
If the pH balance in a bed is below 6, the soil may be too acidic for most vegetable plants. Add a soil amendment that includes ground limestone or aged steer manure. Both these materials neutralize the acid in the soil, bringing the pH level up. Add enough to raise the pH to between 6 and 6.9 for optimal growing conditions.
If the pH balance is above 7, the soil is too alkaline. Pine needles, peat moss or sulfur have high acid content, so adding one of these organic materials to the soil neutralizes the alkaline content, balancing the pH levels. Again, add only enough to achieve the proper pH balance.
Check the Soil Throughout the Growing Season
As the garden plants grow, the nutrient levels change as do the pH levels. Monitor the beds using a soil test kit and the pH meter. Use the readings to add the appropriate type of fertilizer as well as soil amendments throughout the growing season.