Will City compost be alright to use

Community Community No dig gardening Preparing the ground Will City compost be alright to use


This topic contains 2 replies, has 2 voices, and was last updated by  Helle 4 years, 10 months ago.

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    I have just taken on an allotment (I’m in Denmark) that is quite overgrown with weeds.
    All the usual suspects: A lot of horsetail, a little couch grass, a few docks, a lot of field bindweed some ground elder…. plus some annuals especially common nipplewort and spring vetchling, spring pea.
    There are also some raspberries gone wild.
    I have so far dug out the raspberries, and potted them in the hope that they can be reused, I also removed some old stumps, but am planning not to dig much more (maybe the docks), except that I need to level an area, where a previous owner has moved a lot of soil into a pile, for unknown reasons.

    I have also used a lawn mower to control the weeds a little, so I can see what’s happening below. All these clippings will be going into the compost bins, that we are making as one of the first things on the site.

    I plan to clean the plot little by little (it’s 300m2).
    I do not have any compost right now, so I’m planning on covering/mulching? the areas that I want to use next summer with cardboard and woven polythene for the rest of the season, and then remove the polythene, add more cardboard and a thick layer of compost in the spring, where I can get all the free city compost that I can use.

    My question is really that, since I’m not a native English speaker, I get confused around the word compost. It seems like it is used for both the bagged peaty “soil” you can buy in garden centers and also the homemade “rotted” greens that you make in a compost bin – which one is used in no dig?

    I’m a bit worried that the city compost (made from green waste) might be too potent. The nutritional values for the compost are as below – will that be ok, and can you plant and sow directly in this, or do you plant the plug plants so deep that the roots connect with the underlying soil?
    Also, I’m reading that you sow directly in the compost – will that be ok, or do I need to cover the compost with some ordinary topsoil or store-bought garden “compost”?

    Fertilizer value Unit Tested value
    Nitrogen kg/m3 3,5
    Phosphorus (in citrate) kg/m3 0,50
    Potasium K-total kg/m3 1,9
    Magnesium, Mg-total kg/m3 0,60
    Lime effect CaCO3 kg/m3 6,6
    C/N ratio 12:1

    Physical properties Unit Tested value
    Bulk density kg/m3 498
    Used sieve mm 15
    Dry matter % 63
    Organic matter (humus) % of dry matter 20-25 (24)
    Lt 10mS/cm 0,999
    PH-value, 6,8-8,6 (7,3)



    Welcome ,
    You are indeed fortunate in getting any sort of analysis for your City compost. All one can hope for here is that it meets a standard known as pas100, and that its relatively free from junk.
    You should notice when its delivered if its ‘hot’ to the touch, indicating that its still decomposing, and should be allowed to finish (ripen) before application.Ideally, get it early, and if possible, insert a compost thermometer to record the temperature trend. 60 deg C should be the maximum, falling back to ambient air temperature. Another indicator would be the population of the heap by woodlice- they like it ‘cosy’ but not hot!.
    There is no definite definition of compost, beyond being a blend of plant based material in the process of decay.All will work to some extent for our purpose, which is to provide a natural environment for fungi, bacteria and organisms to perform Natures miracle, which requires air, moisture and minerals. Your compost feeds these, not the plants directly*
    *research Dr Elaine Ingham
    Yes, you can plant into the compost layer.Most plants are presown and grown on in pots or trays (modules) prior to planting out, especially in the early Spring period.See the books and videos produced by our host.
    The plants will determine whether they require to go down into the soil.My experience of no-dig is that my plants thrive, and grow more roots,both directions ,sideways and down.When harvesting, cut off the plant, leave the roots intact in the ground.They will generally rot away, leaving a clear passage for other roots, organisms and water to travel



    Thank you so much for a thorough answer.
    Yes we are fortunate with the compost analysis – there are even more values than those I put i my post – i.e. the amount of heavy metals, to prove that the level is below what is legal.
    I have just ordered the book “How to create a new vegetable garden by our host, but it has not arrived yet, and am binge watching his videos.
    There is so much to learn from Charles 🙂

    I will make sure to get the compost as early as possible (it is not delivered, I have to get it with a trailer and a shove – hard work, but good exercise. Normally it is not available before late March, and I will keep in mind that is has to mature, if it is still hot.


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