BLACK GOLD® Garden Amendment Guide

Black Gold® amendments cover everything from basic coir, to premium peat moss, compost, and earthworm castings.  Each has an important application in your garden and landscape planning. For product basics and best uses, follow this simple guide.


BG_JSTCOIR-2cu-FRONTFew natural amendments hold water and air as well as coir. It is recommended as an amendment where extra organic matter and increased water holding capacity are needed. Apply it as a broadcast amendment in raised beds or add it to containers or small beds on a plant-by-plant basis.

OMRI® Listed BLACK GOLD® Coir is derived from coconut husks and a sustainable byproduct of the coconut industry. Unlike peat moss, it breaks down more slowly and maintains a more neutral pH (5.5 to 6.8) than peat (3.5-4.5). Our premium coir is fine and highly processed. It is a popular media for professional hydroponic growers, but it also does wonders as an additive to container plantings and small garden beds. Evenly work it into the soil for best results and consider adding a layer to the top of container plantings for added water retention. (Just be sure to water thoroughly to fully soak pots at each watering!)

Coir should be added to plantings in spring, but it can also be incorporated into fall containers. Gardeners living in drier regions, such as the American Southwest, should definitely add coir to their plantings to reduce the need to water. 

BLACK GOLD® Garden Compost Blend

BG-GRDNCMPST-BLND_1cu-FRONTFew amendments enrich plantings as well as compost. It is the best broadcast amendment to add to all of your raised and in-ground garden beds in spring. BLACK GOLD® Garden Compost Blend contains a quality mix of compost, bark, and Canadian sphagnum peat moss to improve the texture, water-holding capacity, and overall quality of your garden soil. Even better, it is OMRI® Listed for organic gardening.

Compost can be applied and tilled into the soil or used as attractive mulch for vegetable and flower beds. To calculate how much compost (or other broadcast amendments) to apply in cubic yards over a defined area, we recommend the following formula.

Amendment Application Formula for Beds

For square or rectangular beds, multiply the bed’s length by its width to get square footage (L *W= ft2). If you wish to lay mulch 2-inches deep, then have a look at the table below to get the corresponding square footage covered by 1 cubic yard of compost, mulch, or peat moss. Then divide the square footage in the table that matches the 2-inch depth.

For example: If you had a 12-foot x 24-foot bed that required 2 inches of peat moss for tillage, calculate 12 feet x 24 feet = 288 square feet, then from the chart, you can determine that 288 ft2/162 ft = 1.78 cubic yards of mulch. 

Square Feet to Cubic Yards Conversion Table

1 cubic yard of an amendment or mulch will cover the following square footage to each depth.

Depth of Amendment

Square Footage Covered


324 ft2


162 ft2


108 ft2


81 ft2

To calculate the square footage of other bed shapes, please click here for an excellent reference. You can also click here to view a handy mulch/amendment calculator.

Spring is the best time to liberally apply compost to gardens, but if you also plan to do significant fall planting, reapply in autumn. Organic matter breaks down over the course of the season and needs to be replenished. If you plan any winter or cold-frame gardening, apply compost as both an amendment and protective mulch.

BLACK GOLD® Earthworm Castings Blend 0.8-0.0-0.0

BG_EARTHWORM_8QT-FRONTRich in nitrogen and soil microbes, BLACK GOLD® Earthworm Castings Blend 0.8-0.0-0.0 is a combination of pure earthworm castings and Canadian sphagnum peat moss. It is OMRI® Listed, making it a choice amendment for organic gardening. Apply it to vegetable gardens and landscape beds needing added organic matter and a boost of natural nitrogen.

In spring, add it to garden beds—working it deep into the soil. Later in the season, add it to plantings as an enriching mulch, or top dressing. It can also be added to container plantings as supplemental mulch.

Mix a cup into a gallon of water to make enriching “castings tea” to add to potted or garden plants during the growing season. This is most recommended for foliage plants needing added nitrogen.

BLACK GOLD® Canadian Sphagnum Peat Moss and Peat Moss Plus

BGPeatMoss2.2cu Front-WEBPeat moss is naturally organic and one of nature’s most effective soil amendments. It quickly adds loads of organic matter, which increases soil water retention and aeration, and its acid pH (3.5-4.5) will lower the pH of alkaline soils. This makes it the perfect amendment for clay-rich and alkaline soils. Acid-loving plants, such as blueberries, rhododendrons, azaleas, and camellias, also grow best in garden soil amended with peat moss.

Apply peat to the soil in spring and till it in well. Peat moss is naturally dry, so we recommend opening bags and lightly wetting the contents before tilling. This will reduce airborne peat and ensure it incorporates well into your soil.  If you have loamy soil that is more friable, consider turning the peat into the soil by hand. Much of the peat will break down in a season, so if you plan to plant new perennials and woody plants in the fall, be sure to add additional peat at planting time.

Compressed bales of BLACK GOLD® Canadian Sphagnum Peat Moss go far—with our largest bales covering as much as 3.8 cubic feet. BLACK GOLD® Peat Moss Plus is just offered in smaller bags; the easy-to-wet formula is recommended for indoor and outdoor container gardening. Both are OMRI® Listed for organic gardening.

BLACK GOLD® Perlite and Vermiculite

BG_PERLITE_8QT-FRONTTwo of the most important basic mineral additives to potting mix blends are perlite and vermiculite. Both are essential potting mix components. They can also be used on their own for leaf- and stem-cutting propagation or at-home hydroponic growing.

Perlite is a porous, lightweight, expanded volcanic rock that improves the drainage of any growing mix. It is also an essential mineral for hydroponics. It holds water well and retains nutrients, but it also dries quickly and keeps roots well aerated.

Vermiculite is a spongy, absorbent mineral derived from mica. Its properties are similar to perlite, but its spongy structure holds more water and retains more nutrients. Vermiculite is also more delicate and will lose its structure and effectiveness faster than perlite.

BG_VERMICULITE_8QT-FRONTBoth BLACK GOLD® Perlite and Vermiculite can be added to Peat Moss Plus, Just Coir, Garden Compost Blend, and Earthworm Castings Blend to formulate mix-your-own potting mixes. Here are several mix recipes to try:

Seedling Mix

Mix 2 parts Peat Moss Plus to 1 part Vermiculite and 1 part Perlite for a fine mix for seed starting and seedling culture.

Water-Holding Potting Mix

Mix 2 parts Garden Compost Blend, 1 part Just Coir, 1 part Vermiculite for an organic-rich potting mix that holds water well.

Well-Drained Potting Mix

Mix 1 part Peat Moss Plus, 1 part Garden Compost Blend, 1 part Vermiculite, and 1 part Perlite for a fast-draining mix that also holds water and nutrients.

Potting Mix for Foliage Plants

Mix 2 parts Earthworm Castings Blend 0.8-0.0-0.0, 1 part Peat Moss Plus, 1 part Perlite for a nitrogen-rich potting mix that holds water and nutrients while also providing good drainage.

We use only the finest ingredients in all of our amendments, so gardeners can be confident when choosing these and other BLACK GOLD® Products.