Amending Natural Soil

Choosing Amendments

• 1

  Evaluate the physical structure of the soil. Pinch soil between thumb and forefinger, feeling for a grainy structure that indicates the presence of sand. Soil that is easily squeezed out into a ribbon-like shape has a significant proportion of clay. Clay soils feel sticky, and sandy soils feel gritty.

• 2

  Examine the color of the unamended soil. Marginal soils will be drab gray or olive and have a musty smell that indicates fungal growth.

• 3

  Amend soils overly heavy in clay by adding sand at a rate of one part sand to 80 parts soil.

• 4

  Collect a soil sample from a depth of at least 6 inches and have it evaluated by a local agricultural extension. A soil test is the only way to identify specific nutrient deficiencies, and any amendment plan should be formulated according to its results.

• 5

  Amend soils in spring or fall, but avoid tilling in wet weather. Soils should be allowed to rest at least one season before planting.

• 6

  Add well-decomposed amendments to sandy soils, such as compost or aged manure, to increase moisture and nutrient retention. Clay soils require amendments with higher permeability, such as wood bark or perlite.

• 7

  Choose additional amendments based on soil appearance and test results. Options include wood bark or chips, perlite, vermiculite, straw, compost, manure, peat moss, grass clippings, biosolids or almost any other organic material.

Applying Amendments

• 8

  Remove existing plant growth before adding amendments, using a spade or sod cutter. Skid-steer tractors are useful for larger areas.

• 9

  Neutralize excessive weed growth by applying a glyphosate herbicide. Allow a few days for dissipation before continuing the amendment process.

• 10

  Use a garden spade, mechanical tiller or tractor to turn over the soil to a depth of 10 to 12 inches. Shovel a layer of 3 to 6 inches of soil amendment over the tilled earth.

• 11

  Mix the amendment material in well, to a depth of 10 to 12 inches. Larger areas may require the use of tractors or mechanical tillers.

• 12

  Irrigate recently amended soil several times before planting.

• 13

  Apply surface dressings of soil amendments at regular intervals thereafter. Healthy garden soil requires the regular addition of organic material.