Meleah MaynardPeat-free potting soil options

Most every commercial potting mix contains sphagnum peat moss because it’s a good, lightweight, organic amendment that improves drainage, as well as water retention and air circulation. The downside to peat moss is that it isn’t a sustainable resource. Peat moss is the decomposing remains of living sphagnum moss, and it is harvested at unsustainable rates from bogs in a manner than involves scraping off the top layer of the living moss to get to the saleable product below.

I grow all of my veggies and ornamentals without using peat moss.

I grow all of my veggies and ornamentals without using peat moss.

This process destroys centuries-old bogs, doing away with wildlife habitat, releasing C02 into the air, and eliminating wetlands that help prevent flooding. Because of this, conservationists and scientists all over the world have been pushing for limits and even bans on peat moss harvesting.

In Britain, for example, where peat is often burned for fuel, harvesting has become so intense that the government has set goals for phasing out peat for home gardening use by 2020. Professional growers will need to go peat free by 2030. For more information, check out the Royal Horticulture Society’s website.

Most of the peat used by the horticultural industry in the U.S. comes from Canada where talk of limits and bans is also heating up. So, whether you are concerned about the sustainability of peat of not, now seems like as good a time as any to explore some peat-free potting soil options.

Topping the list of sustainable peat alternatives is coconut coir. Coir is coconut husk fiber, a byproduct of the coconut industry in Southeast Asia where it is largely considered waste. Dehydrated and sold as small bricks or bales, coir can hold nearly 10 times its weight in water. In fact, researchers at Auburn University and the University of Arkansas recently compared peat and coir and found that the two were on par as soil amendments. Like peat, coir is low in nutrients, but it is also less acidic.

Coir-brickYou can buy peat-free potting soil mixes, which are slightly more expensive than peat-based blends, and consist primarily of compost, pine bark (or another type of bark) and coconut coir. Some mixes may also contain materials that help to improve drainage such as perlite (a type of volcanic ash) and vermiculite (a mineral that comes with its own set of environmental challenges).

You’ll save money if you make your own peat-free potting soil. And it’s easiest to buy your ingredients and mix them in a wheelbarrow before filling your containers. Here are a few recipes that are easy, affordable and still offer good drainage.

For seed starting: Wet coir according to package directions and use it as you would peat in trays or other containers.

For seedlings: 1 part compost; 2 parts coconut coir; 1 part builder’s (sharp) sand

For ornamental plants: 1 part coconut coir; 1 part compost; 1 part good garden topsoil; 1 part builder’s sand or perlite

For edibles: 2 parts compost; 2 parts coconut coir; 1 part builder’s sand

Keep in mind that compost makes a good slow-release fertilizer. But container-grown plants, especially edibles, will need additional nutrients throughout the season. Some good choices include: additional compost, bone meal, feather meal, vermicompost (worm poo), fish emulsion, cottonseed meal and alfalfa meal. Earth-friendly fertilizer blends can also be purchased by the bag. I particularly like some of the organic products offered by Espoma.

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Meleah Maynard

About Meleah Maynard

My name is Meleah Maynard and I garden in crazy-ass cold, zone 4 Minneapolis, Minnesota. My first book, co-authored with Jeff Gillman, Decoding Gardening Advice: The Science Behind the 100 Most Common Recommendations, was recently published by Timber Press. I don't have a hort degree. I'm a longtime journalist and master gardener who loves asking people questions, doing research and learning something new every day. I hope you like my blog here on GardenDrum and you read my full blog at Everyday Gardener

4 thoughts on “Peat-free potting soil options

  1. Thanks Meleah. I didn’t know peat moss was a finite resource and what its harvesting did to bogs. I will try your recipes using the coir instead. Always learning. Fantastic .

    • Hi Julie,
      Thanks for your note. I love to learn too! And I hope you like the coir mixes.

  2. Christina Tassell on said:

    Hi Meleah,
    My good friend lives in Minneapolis and we share a love of gardening.
    Although I live in sunny Adelaide, South Australia, our temperatures are very often similar but at different seasons of course. I complain of hot drying winds she complains of snow falls and more snow falls!
    Love your concern re the peat bogs, it has long been of concern to me.
    Cheers
    We have just had 3 days of glorious rain.
    Christina

  3. Hi Christina,

    I’ve never thought of our temps being similar sometimes, but I suppose that’s true and, somehow, that makes me feel a lot better about living here because Australia seems wonderful to me! – m

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