Can You Put Weeds in the Compost Pile?

“Is really ok to use weeds when doing compost? Do you have to make sure that they are in a certain stage of growth? Because I really don’t have the time to study them as I pull.” Question from Erin of Kirkwood, Missouri

Answer: You can certainly put weeds in the compost pile if they meet two criteria: (1) They are not sickly or obviously diseased, or (2) they are not noxious weeds, such as bindweed or Canada thistle, that have set seed. I would also avoid trying to compost any perennial weed roots. A well-tended compost pile should heat up enough to kill weed seeds, but when it comes to noxious weeds, I would not take the chance and recommend that other gardeners apply the same precaution. The heating process in the compost pile can also kill any diseases, but once again, I think it’s smarter to err on the side of caution.

Happy gardening,

Jessie Keith

Black Gold Horticulturist

Can I Use Black Walnut Leaves for Compost?

Can I Use Black Walnut Leaves for Compost?

“I have several black walnut trees in my yard. Would it be alright to use the leaves in the compost? Question from Raymond of Holt, Michigan

Answer: I would not recommend it. As you surely know, black walnut trees (Juglans nigra) excrete the toxin, juglone, which is deadly to quite a few ornamental plants. The toxin helps reduce competition, making black walnuts bad trees for small home landscapes. Who wants a deadly tree around? Still, black walnuts are beautiful and have edible nuts that feed wildlife, so they are best reserved for more wild areas or fencelines far from the home garden–unless you plant nothing but tolerant plants.

Juglone is largely excreted by the roots, but it is also found in lower quantities in the wood and leaves. The toxin can leach from leaves into compost in small quantities. That’s why you need to be careful about what you plant near a walnut tree and where you put walnut leaves, which are best taken to the woods, fenceline, or bagged for disposal.

Because you have a black walnut tree, it would be prudent to get to know plants that are resistant and sensitive to these trees. Please click here for a great list provided by the Morton Arboretum, a world-class tree resource.

Symptoms of Black Walnut Toxic Syndrome

Keep in mind that there is no cure once sensitive plants have been significantly impacted by juglone. Exposure signs include yellowing, wilt, stunted growth, and finally death. It may take plants months to die after exposure.

Happy gardening,

Jessie Keith

Black Gold Horticulturist


How Long Does Compost Feed Plants?

How Long Does Compost Feed Plants?

“How long does compost feed plants? And if you have compost in the ground, do the plants still need fertilizer? I use plant-based food scraps, grass clippings, and shredded paper for trench composting. It breaks down very quickly here in the Sonoran Desert.” Question from Jacqueline of Casa Grande, Arizona

Answer: The value of compost to plants depends on how long it takes to break down. Compost adds needed structure, water-holding capacity, aeration, and microorganisms to garden soil. Overall, it feeds and enriches soil, but its nutrient profile depends on what you feed into your compost pile. For example, if you add lots of eggshells your compost will have higher calcium content. With that said, you should also add balanced fertilizer to your garden beds–especially where soils are nutrient-poor. As your compost breaks down and disappears, it is no longer working its magic, so keep it replenished. And, if you run out you can always supplement further with products that are high in organic matter, such as Black Gold Garden Compost Blend, Just Coir, or Canadian Sphagnum Peat Moss.

Happy gardening!

Jessie Keith

Black Gold Horticulturist

Can I Grow Plants in Pure Compost?

“I have some large compost bins, which produce a lot of compost. Can I plant things in pure compost, or do I need some “dirt” with inorganic materials for the best results?  How much inorganic material do I need?” Question from Naomi or Oakdale, California

Answer: Congratulations on your composting success! Compost is one of the best garden amendments available. You can plant in straight compost, but I suggest incorporating it into your sandy garden soil or mixing it with other additives if you want to use it for container plantings.

Compost as a Garden Amendment

When using compost to fortify gardens, incorporate it evenly into your natural soil. Add it liberally if your soil is of very poor quality–especially if you want to grow crops that need fertile soil, like fruits and vegetables. You might also consider building raised beds to make the most of your compost bounty.

Compost as a Potting Mix Additive

If you plan to use your compost for container plantings, include other additives to encourage better root growth in the long term. These include Black Gold Canadian Sphagnum Peat Moss, perlite, and vermiculite.  The peat moss with lighten the mix and give it more structure and porosity, while the perlite will help increase drainage. Vermiculite holds water, adds porosity, and holds and distributes nutrients. A well-rounded potting mix would include 40% compost, 30% peat moss, 20% perlite, and 10% vermiculite.

I hope that this helps, and keep composting!

Jessie Keith

Black Gold Horticulturist

Is Bat Guano Good for Flower Beds?

“I have a large amount of bat dung in our barn and have heard that it is an excellent fertilizer for flowers. Is that true?” Question from Catherine of White Cloud, Michigan

Answer: Bat guano makes an excellent plant fertilizer once it has been composted. Fresh bat guano is rich in nutrients, particularly nitrogen, but it needs to be broken down and mellowed before use. This is the same for any manure (cow, horse, etc.) that you may want to add to the garden.

To compost it, pile up the guano, layering in grass clippings, dry leaves, vegetable waste, and/or straw as you go. The higher the pile, the better. Do this in a composter, if you have one, or in a convenient spot outside of your barn. Once the pile is complete, moisten it, and allow it to naturally compost/decompose for a couple of months. In this time, the pile will heat up in the center. Turn it with a spade or garden fork every two weeks and keep it moist to ensure that the whole pile gets composted. Once it is ready to use, it will be cool in the center and very crumbly and soil-like.

To reduce its high nutritional punch, consider cutting your composted guano with standard compost, such as Black Gold Garden Compost Blend, before use. Because guano is high in nitrogen, which encourages foliage growth rather than flower development, mix in a granular fertilizer formulated for flowering plants before adding it to your beds.

Keep gathering and using your guano! It’s good stuff for the garden.

Happy gardening,

Jessie Keith

Black Gold Horticulturist

How to Amend Around Mulched Flower Beds

“On an annual rotation, what do I do with my mulch? Do I strip and reapply every year? How do I amend my soil in a flower bed that already has perennials? Do I  just topdress? Or dig around the perennials and mix with native soils?” Question from Tim of Springfield, Pennsylvania

Answer: Good questions! I am assuming that you apply bark mulch, which is generally slow to break down, especially if less processed when applied or comprised of cedar or other evergreen barks. I will also assume that you apply it at the standard depth of at least 2 to 3 inches.

You have several options for improving the soil of your mulched annual and perennial beds.

Annual Beds

  1. Switch to a mulch that feeds the soil. Bark mulch is notorious for binding essential nutrients, namely nitrogen, and breaks down too slowly to rapidly feed your soil. Mulching with composted bark, compost, or leaf mulch (all of which quickly integrate into the soil) will do the duel job of protecting against weeds and feeding your soil. (OMRI Listed Black Gold Garden Compost Blend is an excellent choice for the soil surface and as an amendment.)
  2. If you want to stick with bark mulch for your annual beds, do a soil re-haul in the spring, once your soil is warm enough to work. Neatly rake your mulch onto a tarp and generously and deeply work compost and peat moss into your beds. Work it down with a garden fork or tiller to a depth of at least 8 inches. This is also a great time to add slow-release flower fertilizer for the season. Then plant your annuals first and re-mulch afterward to avoid getting mulch into the planting holes.

Perennial Beds

  1. Once again, consider switching to a mulch type that better feeds your soil and garden plants, and be sure to fertilize your perennials yearly.
  2. If you want to stick with bark mulch, you could leave 6-inch a ring around each perennial and apply either compost or earthworm castings on the surface annually in the spring. Even when applied to the soil surface, the quick-to-decompose organic matter will feed your plants and soil microorganisms.
  3. If you are really concerned about the soil quality of your perennial beds, do a soil re-haul in the spring. Start by digging your perennials (this is also a great time to divide them and/or redesign your beds), then follow the same steps listed above. Perennials tend to set deeper roots than annuals, so it pays to amend the soil a bit deeper.

I hope that these tips are helpful!


Happy Gardening!


Jessie Keith

Black Gold Horticulturist


Black Gold® Garden Compost Blend

OMRI Listed Black Gold® Garden Compost Blend contains a rich mix of Compost, Canadian Sphagnum Peat Moss, and Composted or Aged Bark. It is perfect for fortifying garden beds with annuals and perennials, vegetables and herbs, and indoor and outdoor containers. Give your garden plants a natural boost this season with Black Gold® Garden Compost!

View the Product Info Sheet PDF

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.