Healthy soil is made up of many components. Soil texture, drainage, and nutrient content are all important ingredients that contribute to plant health. One of the best ways to improve the ability of the soil to hold moisture, provide nutrients, and allow drainage is by adding organic matter into the soil.
Adding Organic Matter to Soil
- Rototilling usually mixes organic matter into the top 4-6 inches of soil, heavier-duty tillers can reach depths of 8 inches
- Aim for 5% organic matter in garden soil
- Soil and organic matter type and amount already present will determine how much organic matter should be applied
- Certain native plants adapted to low-organic matter desert soils may not need additional organic matter or fertilizer
Caution should be used when tilling in organic matter. Excessive tilling can cause compaction beneath the tilling zone. This is especially the case if the soil is too wet. To mitigate soil disturbance and compaction, use a spading fork and disturb as little of the ground as possible.
Another way to incorporate organic matter is to simply place the organic matter on top of the soils and plant into it. When applied in this manner, organic matter will act as a temporary weed barrier and mulch for moisture retention. The organic matter will take longer to integrate into the existing soil.

Additional Resources:
West
Oregon: Improving Garden Soils With Organic Matter
Utah: Solutions to Soil Problems V. Low Organic Matter
Southwest