Score: 4/5


Black Gold Natural & Organic Potting Mix | Review by Gardens of CascadiaSun Gro is one of the leading US horticultural companies, mostly known for their soilless, peat-moss-based growing mixes. Their Black Gold® Natural & Organic Potting Mix is a high quality, versatile organic mix recommended for all types of pot-grown vegetables, herbs, and flowers, from indoor to outdoor containers, bedding plants, hanging baskets, and window boxes. It is also recommended for vegetable gardens and raised beds.

The main base is Canadian sphagnum peat moss and bark, combined with an impressive mix of premium organic matter and drainage enhancers. This is enriched with organic fertilizer, earthworm castings, pumice, and perlite. Listed by the Organic Materials Review Institute (OMRI), this rich, loamy soil ensures that your organic food crops remain chemical-free.

The Black Gold® Natural & Organic Potting Mix is pre-mixed and ready to use straight out of the bag. Therefore, it doesn’t require any preparation before its use, as peat moss does when purchased as-is. Available in multiple package sizes, it is a quite affordable mix, especially for a product containing such a multitude of high-quality, premium, organic ingredients.

This makes it perfect for general potting use. But how good is it for cannabis? It has two things going against it: one, that cannabis growers are recently moving away from peat-moss-based growing mixes, preferring purely coco-coir-based ones. And two, it contains dolomite lime, which decreases the soil’s acidity. While this is good for general use, as it gives us a balanced soil, cannabis growers may prefer a more acidic mix, as cannabis plants require slightly acidic soil to thrive.

Base and Composts

The Black Gold® Natural & Organic Potting Mix contains an excellent blend of natural ingredients that make up its base. Canadian sphagnum peat moss is able to hold efficiently water up to twenty times its weight and thus enhances the plant’s hydration. It is also antibacterial and pest-free and encourages the proliferation of a healthy community of microorganisms at the root zone. Lastly, peat moss contains sulfur, which is used by the plant in the creation of terpenes. These terpenes are responsible for color, smell, and taste, as well as multiple micronutrients that get passed to the plant. Therefore, peat moss is an excellent material to keep the soil rich in nutrients and well hydrated.

Coconut coir is also included in the mix, to improve overall drainage and aeration. Although it’s a fairly recent addition to pre-mixed potting soils, it is becoming increasingly popular, with many growers using it to replace peat or to mix the two mediums together. Coco coir takes longer to break down naturally, meaning less maintenance is required as it doesn’t have to be replaced as quickly or as often—plus, it is an affordable ingredient that helps to keep costs down.

Finally, the Black Gold® Natural & Organic Potting Mix contains almost one-quarter of compost mix which varies by region and may be derived from composted rice hulls, composted mushroom casing mix and/or composted dairy manure. The compost mix also includes seafood and shrimp meal to enhance phosphorus and calcium, which contributes to healthier blossoms and leaves free of black spots.

Aeration and Drainage

To improve water drainage and aeration, perlite has been included in this mix. Perlite is a substance derived from crushed volcanic rock that is ground down and mixed in the soil to increase the spacing between soil particles. It effectively makes it very difficult to overwater the plant—consequently, it minimizes the risk of the soil or the roots rotting.

Composted and aged bark is another organic ingredient used in the Black Gold® Natural & Organic Potting Mix to increase air capacity and air circulation through the soil, thus improving oxygen availability to the plant roots.

Mineral Additions

The Black Gold® Natural & Organic Potting Mix includes Sun Gro’s exclusive, innovative potting mix additive, RESiLIENCE® (the company’s trade name for horticultural silicon). RESiLIENCE® is an all-natural, water-soluble mineral that improves trichome development, allows for earlier flowering, increased stem diameter and a longer period before wilting, supports root growth, and helps plants recover from infrequent watering.

The mix also includes dolomite lime, bringing calcium and magnesium to the mix. Used in the right dosage, dolomite lime contributes to plant development and general health by compensating for the natural loss of minerals. However, while peat moss is known to increase acidity, dolomite lime may decrease it. If your plants require acidic soil, you need to take this into consideration.

Soil Amendments

This product also contains a blend of organic grade fertilizer to fertilize and deliver nutrients to plants, increasing the efficiency of your organic crop.  Worm castings are another natural ingredient of the mix that acts as a fertilizer. Many growers have found including it in potting soil increases the overall yield, shortens the germination cycle, and protects plants from disease—all without the use of any chemicals.

One of the most innovative ingredients in the mix is mycorrhizae, a nutritional fungus that grows symbiotically with the roots of a plant. It acts as an extension of the plant’s root system, increasing the plant’s capacity to reach water and nutrients. Although mycorrhizae naturally occur in soil, they grow slowly. By adding some to the soil, you speed up the process. The result is usually a maximized yield—both in terms of quantity and quality.

Quick Summary—Pros and Cons


  • Made by a reputable company known for its high-quality products
  • Certified organic, listed by the Organic Materials Review Institute (OMRI)
  • Contains a great range of organic ingredients, some of which are innovative,  to help water retention, drainage, aeration, and growth
  • Ready to use straight out of the bag
  • Affordable price


  • Some users have reported gnat problems, especially when the soil is used indoors.
  • The dolomite lime contained in the mix may decrease your soil’s acidity—something you need to take into consideration if your plants require acidic soil.