Gardening

What is “Black Earth”?

20150422BGardeners seem to believe that the darker a soil is, the better it is. And that does tend to be true in many cases. But not always.

In my part of the world (Northeastern North America), there is a product widely sold as “black earth” that is very popular with gardeners. It is also very cheap. I’d like to say dirt cheap, but it is actually cheaper than “dirt” (topsoil). It is sold by the bagful in garden centers and even supermarkets where people load up their trunks with what they think is top-quality soil at rock-bottom prices. They’re very unlikely to be happy with the results.

Of course, this product isn’t black earth. Black earth (the real stuff) is a type of soil officially called chernozem. It is very rich in humus, chock full of NPK and ideal for growing most nutrient-dependant plants, including vegetables. Its usually found in what were originally low-lying, marshy areas, now mostly drained and being used for agriculture. If you really could get your hands on true black earth at a reasonable price, it would be wonderful: pretty much the ideal garden soil!

But the stuff sold as black earth is not chernozem, at least not in the eastern part of the continent (I’m sorry I can’t generalize: the term “black earth” can mean different things in different areas). In fact, it is not soil at all, but black peat, a very dark-coloured type of peat found at the bottom of sphagnum peat bogs, under the more widely used blonde peat (the top layer) used in most quality potting mixes and the somewhat decomposed brown peat moss (middle layer), a lesser quality peat used mostly in soil mixes for outdoor gardens.

Black peat is the lowest quality peat. It contains no fibre and, unlike other peats, compacts readily and doesn’t hold nutrients well. It needs to be amended with limestone for most garden uses, as its pH is much too low for most plants. It can be useful for amending clay soils (if you can get it to mix with clay: good luck with that!) and sandy soils, but its effects don’t last. Blond or brown peat are much better choices for this use.

But “black earth” (black peat) remains popular in the soil packaging industry… essentially as a colorant. No, packaging people will never say that, but essentially, that’s the case. They know gardeners associate a dark soil color with good quality soils, so… give the people what they want.

The problem is, you never know what you’re getting with a product labeled “black earth”. It can be nearly pure peat. One product I saw listed as ingredients: peat, humus, limestone, dolomite. Well, the peat itself is humus and dolomite is a type of limestone. So this product is essentially pure black peat with enough limestone added to bring the pH up to an acceptable level. You should never try growing plants in this. Yet the label says “earth” and many people assume that means they can use it directly from the bag for containers, vegetable gardens, etc. And that will lead to disaster. Very few plants will survive for long in black earth if it is just limed peat moss.

Other “black earth” products do contain topsoil and may be labeled “black earth soil” or “black earth topsoil”. They’re slightly better, but again, you’d be better off with regular topsoil, which is usually amended with higher quality brown peat.

In a nutshell, “black earth”, unless you are certain you are really getting true chernozem (and that may be possible in certain parts of the world) is at best a lower quality product, certainly not the quality product many gardeners think it is. At worst, it is strictly a soil amendment and not “earth” that you should try growing plants in. Personally, I avoid it like the plague.

But it will probably continue to be a big seller because people remain convinced dark soils are the best. But if black earth really were the best, why is it always the cheapest “soil” on the market? I know your mama told you this, but it’s worth reminding you from time to time: you get what you pay for!

Larry Hodgson is one of Canada’s best-known garden communicators. He has notably been editor-in-chief of HousePlant Magazine, Fleurs, Plantes et Jardins, À Fleur de Pot and Houseplant Forum magazines and is currently the garden correspondent for Le Soleil and radio garden commentator for CKIA-FM Radio. He has written for many garden publications in both the United States and Canada, including Canadian Gardening, Harrowsmith, Horticulture, Fine Gardening and Organic Gardening. He also speaks frequently to horticultural groups throughout Canada and the U.S. His book credits include The Garden Lover’s Guide to Canada, Complete Guide to Houseplants, Making the Most of Shade, Perennials for Every Purpose, Annuals for Every Purpose, and Houseplants for Dummies, as well as nearly 60 other titles in English and French. He is a past president of the Garden Writers Association (now Garden Communicators International) and the winner of the prestigious 2006 Garden Media Promoter Award offered by the Perennial Plant Association. He resides in Quebec City, Quebec, Canada.

9 comments on “What is “Black Earth”?

  1. Was thinking about this recently, Larry. Glad to know I’m not alone in thinking it’s a big scam most of the time.

  2. Every year I buy bags and bags of “black earth” at bargain prices because I am a gardener with little financial resources to be used in the garden. I use it to amend my beds and to start new ones on top of newspaper. I feel so ripped off now! That said, I am old enough and experienced enough that I should have known better. I will save the money and buy compost (fewer bags but higher quality). Thanks for the education, sir!

  3. Pingback: Three Years Already – Laidback Gardener

  4. Stephen James

    So this was me last year. I was disappointed when my plants failed to produce much of anything. Any tips on what to do now that I have 200 sq feet of raised planters filled with the stuff?

    • If you could work in at least 50% legitimate garden soil (preferably a brand that doesn’t contain black earth), that ought to help. It’s hard to be more precise, as what soil is available varies so widely depending on where you live.

      • I am a first time gardener and bought 30 bags of the “garden soil” at reno depot and added 1 bag of pelletized chicken manure, as I read more and more, I am learning that my soil probably sucks, when I squeeze it together and poke it, it stays as a black clump. What would you suggest I add to it to amend it before I plant my tomato, bean (pole) and eggplant seedlings (that I have painstakingly nurtured for over 8 weeks) – do I add peat moss? Vermiculite or perlite? Dolomite lime?
        I bought two of those 3-in-1 soil testers and they seem to be pure garbage when it comes to measuring PH or even moisture levels, neither of them give the same readings. And there are so many different types of PH tests that I am confused (and I don’t even know if I should be checking out the PH levels in my soil bc it’s probably not good quality. Thank you so much for your insights and help.

      • It sounds like you ended up with pure black earth. Peat moss would be the most inexpensive way of adding a bit of aeration, but then the soil might become too acid. Vermiculite and perlite would work and not change the pH. As for the soil tester, read this: https://laidbackgardener.blog/2021/01/30/the-3-in-1-soil-tester-a-virtually-useless-tool/

  5. If this is the case – is triple mix a better option? Not sure what I should be purchasing at this point. Thanks for this post – found it most informative

    • Each company makes its own Triple Mix and don’t share their recipes, so it’s hard know exactly what it is, but its usually a good quality product.

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