Amending garden soil means adding substances in order to change its structure or chemical nature. Most gardeners use this technique when they have either high clay or sand content within their soil.
Fertilizing means adding nutrients to the soil. Even gardeners with dark, rich, crumbly soil will fertilize from time to time to give plants an added boost and to keep their soil from becoming depleted of nutrients.
Amending Clay Soils
Areas with high clay content will benefit from the right amendments. Most garden experts will suggest using organic matter that breaks up clay to facilitate the movement of air and water. Good examples to use are 3 – 4” of aged manure, compost, grass clippings, decomposed plant material, or wood chips. While these substances have the benefit of adding certain nutrients to the soil, they can also deplete your soil of other ones. To hedge your bets, it is wise to add an additional fertilizer to the mix in accordance to your amendment of choice. For example, ‘green’ amendments such as the ones listed above can deplete soil of nitrogen, so consider using fertilizers with higher nitrogen contents.
Some go the extra mile and use an inorganic compound such as pea gravel to further break up the clay. Sand is not recommended as tremendous amounts would be needed. If the proper amount of sand is not used, it will make your clay soil much more compact.
Never begin this process with very wet clay as the amendments will not blend in. Extremely dry clay is unworkable as well. You will have to time it just right! When ready, you will want to dig at least 8” or more and till the 3 – 4” of amendments into the soil.
Top coat your area with your desired organic material and mulch on regular basis to keep a continual amount of nutrients leaching into the soil. Be sure to till in amendments yearly wherever you can, especially when adding new plants.
Clay soils can be cumbersome and labor intensive to work with, but they are generally quite fertile and can support a lot of wonderful plant life once the plants have access to the nutrients. Examples of some plants that can do well in clay conditions: Daylily, Black Eyed Susan, Astor, Sea Holly, Hostas, Beebalm, and Sedums.
Amending Sandy Soils
Soil with a high amount of sand does not retain moisture and is usually nutrient deficient. The good news is… it’s takes less elbow grease to work with!
3 – 4” of organic compost, aged manure or other humus is also effective to mix into sandy soils. They add nutrients and help to bind the sand particles together. (They produce a clumping effect in clay soils by separating the clay) Cultivating a quality store bought garden soil into your sandy garden bed can also do wonders, but is best when combined with other organic material. In addition, many gardeners will use Sphagnum Moss to improve water retention, although when used alone, does not add much in the way of nutrients.
Always remember that most sandy soils will require regular fertilizing. They also will need regular top coatings of organic matter and mulch. Because sandy conditions facilitate very easy drainage, plants that can tolerate dry conditions will usually work best. Some examples: Lavender, Yarrow, Blanket Flower, Sumac, Sedums, and Butterfly Bush.
Amending soil can be hard work but should get easier and easier with each year. It will be well worth the effort when you see your plants grow and flourish.
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