Foxfarm 12 qt. Ocean Forest Potting Soil. This powerhouse blend of premium earthworm castings, bat guano, sea-going fish and crab meal, composted forest humus, sandy loam, and sphagnum peat moss creates a light, aerated texture that is ideal for plant growth. pH adjusted at 6.3 to 6.8 to allow for optimum fertilizer uptake, this all-purpose potting soil mix is suitable for both indoor and outdoor plants.