Soil Amendments

When you have completed your soil test and your soil composition test, you will be ready to think about how to improve the soil. This is done with amendments. Amendments include both chemical and compositional agents.

Chemical Amendments: If your soil has a pH that is too low, you will need to raise it slightly. Conversely, if the pH is too high it will need to be lowered. The most usual agents used to alter pH are lime products to increase the pH and sulfur products to reduce it. These need to be used with care, as it is easy to move the pH too far in the wrong direction. If you did a soil test, then use that as a guide to how much per acre you need to apply. Ideally these amendments should be applied 6 -8 weeks before planting.

Compositional Amendments: These amendments help the soil retain nutrients, as well as create air pockets in clay. As seen in the soil test, your cation exchange capacity will increase with these amendments too.

The most common things used to amend the soil are compost and manure. The first comes from decomposed vegetation, the other from animals. Within reason, these can be added without concern to any soil. To break down clay soils, organic matter is coarse, so small particles will create gaps in the clay thus creating a gap for water and air to fill. In sandy soils, organic amendments will stay within the soil horizon, and fill in some of the many air gaps, and thus help retain nutrients and moisture.

Care should be taken with both compost and manure, as these can both be too fresh. It takes time for decomposition agents to complete their work, and if this stage has not fully finished, then it will result in nitrogen being leached from the plants and soil rather than adding to them.

Mulch can also be a good amendment. Organic mulches such as chopped leaves, hardwood or pine needles, will decompose and enter the soil in a similar way to compost and manure. The sort of mulch dictates how long it takes to be incorporated, but a finely shredded mulch will need to be replaced most years, and a pine needle mulch, perhaps every two or three years, depending on your specific climate.

Whether you make your compost at home or buy it commercially, will depend on how much you need. However, organic soil amendments are as an important constituent in garden maintenance as the chemical ones are. Using both of these soil amendments you will create a soil that is able to foster good, healthy growth in your plants.