The pH level in your garden soil can greatly affect the growth and quality of your plants. All plants, trees, shrubs, flowers and fruits or vegetables obtain their nutrients from the soil and need specific combinations of nutrients in order to do so. Nutrients like Potassium and Nitrogen help plants grow, produce flowers or fruit and fight diseases.
pH levels are graded on a scale of 0 to 14. 0 through 6 indicates acidity while 8 through 14 indicate an alkaline or base substance. Pure water is considered to be neutral at a pH of 7. Testing kits are available to test garden soils at home to determine the starting pH level and what will need to be added for the best plant growth by type.
The pH level of the soil needs to be above 5.5 for Nitrogen to be available for plant growth. For plants to receive Phosphorus this level needs to be 6.0 to 7.0. Bacteria in the soil also help the plants receive and use the available nutrients. While many plants love and thrive in acidic soils too much acid will kill off the nutrients and eventually the plants themselves.
Soils that are too high in acid will not absorb pesticides or fungicides that are applied to control bugs or disease. When pesticides and fungicides are not held in the soil they eventually end up in the runoff and contaminate nearby watersheds and rivers.
All plants have recommended pH levels for obtaining the best growth. Peanuts like a pH level of 5.3 to 6.6, while soybeans do best between 6.0 and 7.0. Walnut trees and asparagus will do well up to a pH of 8.0, considered alkaline. Orchids and blueberries, to the other extreme, can flourish in an acid soil with a level as low as 4.0. Unfortunately, most weeds thrive fairly well across a range of pH levels, but crabgrass and wild mustard can be killed at an acid level below 6.0 on the scale.
A pH range of 6.0 to 7.0 is best for most plants. Test your soil and know what pH level your plants will growth the best with. Plants that require more or less acidity than others should be planted far enough apart for them to thrive. Remember that too high an acid level can cause more damage than good, even for acid loving plants. In addition to damaging plants, high acid levels in the soil can damage any concrete borders. Too high an alkaline level or acid level can corrode steel and this should be considered when setting up trellis.