Too much compost?

This topic contains 9 replies, has 7 voices, and was last updated by  charles 8 months, 2 weeks ago.

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    Hello Charles,

    First of all I would like to thank you for being such an inspiration for me, and other gardeners in The Netherlands. I read your books, implemented lots of your methods and to me it felt like the missing link in my already natural way of growing vegetables.

    At the moment, me and a couple of other gardeners are discussing your no dig/lots of compost adding to the soil way of working. It’s on a Dutch forum, and the discussion is nice but something came up that I had not thought of before. Thats always nice right, when something comes up you havent thought of before 🙂

    But it’s about putting too much compost on your soil and by doing that creating an overkill of nitrogen and phosphorus, this will flow into the soil or go up in the air as ammoniac. I dont have to explain that this is bad for our environment. Also, specifically regarding nitrogen and phosphorus, our government has strict regulations and farmers need to follow these rules, so I would say that gardeners need to do the same.

    It seems like, that if there is too much nitrogen and phosphorus in your soil, it will be bad for the plants as well. See the link below for someone who has some knowledge regarding this topic.

    Too Much Compost – Is It Poisoning Your Garden?

    What are your thoughts regarding this topic?



    Hey Richard,

    I find this topic fascinating too.
    Germany (and also the UK) has rules on how much compost is allowed. I am not sure if they make any sence though.
    It is all about the context for me: in an intensive organic market garden using lots of compost is the key to get healthy vegetables. This is what charles but also Eliot Coleman and J.M. Fortier are looking for when spreading up to 60t / acre.
    Some Books ( in german) I would highly recommend are from austrian Gerald Dunst:
    “Humusaufbau” (Building Soil Humus) and others.
    Here he decribes why using lots of (good) compost is the only way to bring back life and structure to dead Soils.
    And Soils with 2-3% organic matter, like said in the article are basically dead.
    Tillage and Digging will release nutrients and carbon a lot quicker.In a No Dig garden they mostly stay where they are. Dunst proofs this with monthly soil and water tests and he spread 120t / ha to build soil quick. (this is also “illegal” in austria).
    Nitrogen can even get “locked up” when humus is build in soil! Plants will take it as they need it later. Testing water soluable N next to growing plants is a good example: It will be a lot higher next to roots of cabbage plants compared to other low feeders. I have done this myself too.

    Hope this helps and i would love to hear more.




    Hello Richard, and thanks Felix for your reply.
    The article concludes by saying “Keep using compost, but don’t add more than an inch or two a year on your landscape plants”.
    That is exactly what I recommend, normally two inches for intensive vegetable production, which needs more than landscape plants. This article does not address the difference between ornamental and vegetable gardening.

    For compost usage, I don’t see a disagreement here. And animal composts are only one of many I use and recommend.

    Well-made compost in my experience hangs on well to it’s nitrogen. If it did not, my crops could not be as leafy and abundant as they are. Including when I have spread the compost in a preceding November, then I still have dark green broccoli leaves and abundant harvests even in the following October.



    Hi guys,

    I had questions about this topic, also. I live in Texas and garden in raised beds. I began with purchased compost and add homemade plant-based compost (yard waste and kitchen scraps) an inch per bed, per year. Texas A&M soil testing just came back with results of low nitrogen and very high phosphorus and recommended adding nitrogen and ceasing composting for 5 years. However, my plants did well last year. Should I really stop composting? I hate to dispose of all that good stuff instead of using my small composter, and I have no place to store compost.

    Really enjoy your books and website, Charles. Thanks for any tips!




    Hi Stephanie

    Thanks for writing and in your place, I would continue to compost. A problem with such soil tests is how they ignore so much of what makes plants grow – biology! And I am not convinced they present the whole picture of what is available, and when.
    All your soil fauna and microbes are loving your compost and hence your good results.
    For anyone else reading this, I urge caution in taking advice from soil tests. I had one (a free offer) done that said my soil fungi were low, yet growth was amazing, literally.



    Felix – are your numbers based on one cubic metre being around one tonne? That would suggest 6-12cm coverage according to the sources you quote……



    Hey Crew
    Anytime I read how an “authority” has rules on composting, and testing that recommends stopping a natural cycle of waste disposal has me shaking my head.
    I don’t deny what good sciences can achieve but there is far too much reliance on facts and figures along with a healthy dose of fear mongering and control when it comes to the ability to grow sustainable healthy gardens based on principles that have been practised by generations.
    Regards Russell




    Just saw this and rhys with my green waste and manure compost one cubic meter is about 600kg. Yes its a lot of compost, but only initially to build soil. I agree with Russel its time to concentrate on what actually works to improve soil and stop following all these strange rules. With our organic certification you are allowed to have acres full of plastic, use (harmfull..) organic pesticides and N-fertilisers made from factory farming wastes. It all makes no sense to me!

    We spread thick layers of compost and are ready to go!





    I was wondering if all the compost will make the soil acid over time. I know my home make compost is acid and in general all types of fertilisers and compost result in acid soil. Charles never mentions this as a problem?



    Anne, I do mention this, in my Myths book where it belongs.

    Compost and animal manure are not far short of neutral, obviously depending on pH of any soil added. Currently I add a lot of coffee grounds to my compost heaps and people accuse them of being acid but they are pH 6.8.

    After 5 years of adding compost at Lower Farm, my pH had not changed.

    So for anyone reading this, please don’t worry about the “supposed acidity” of compost.

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