Compost very low in nitrogen and roots growing through cardboard

[elisivParticipant]

Hi everybody!

I am starting a no dig market garden in Sweden this year, very excited! I came across a very good and cheap source of compost. It has been heated properly, turned often and 1,5 years old. However it is a bit acidic and very low in nitrogen. I’m thinking that growing in this compost might result in poor growth. How should I fix this problem? Or will the roots search for nutrition themselves?

And one other question; If I put cardboard on the soil and compost on top, would the roots of vegetables grow through the cardboard? When sowing carrots for example? There is a farmer I know who claims that it works that way for hem, but I’m a bit doubtful to try it. I don’t want to risk a bad carrot harvest.

Thanks all so much!

[bluebellParticipant]

Hi Elisiv Sounds like an exciting project.

I have grown using this method for 5 years now and have never measured the PH or nitrogen levels of my compost as I believe that the plants will seek out what they require in terms of nitrogen and that the PH only really matters to a very few plants such as blueberries (even they appear to grow quite well in a neutral soil).

Carrots and similar root very well through card as it disintegrates. Only thing I ever had trouble with was when growing icicle radish in a deep bag, they got so long they started pushing up out of the soil.

[Don FoleyParticipant]

Hi Elisiv,
I’m just curious how you have determined that the compost is acidic and low in nitrogen?

With regard to the cardboard, this should not be a problem but make sure it is really thoroughly soaked when your putting it down.

Don.

[elisivParticipant]

Hi!
Thanks for your replies! I will be buying from the church, they make really good compost of the the leaves, gras clippings, nothing else ;). They send me their test results.

[Don FoleyParticipant]

Hi again,

If its just leaves and grass, and depending on the quantities of each, basically what you have is a nitrogen enriched leafmould which is not the same as compost.
Leaves contain very small amounts of nutrients whilst grass contains about 3-4% nitrogen.
Leafmould is a soil structure improver but adds very little by way of nutrients.

Don.

[charlesModerator]

Elusive, I would be happy to use this compost.
A lot of the value of compost lies in its biological enrichment of soil, as much as chemical.
The nitrogen in grass is perfect balance for carbon in leaves, good work by your church!
As Bluebell says, cardboard no problem. And you need use it only where weeds are thick: I do not use cardboard now my garden is clean of weeds.
Happy growing.

[elisivParticipant]

Thanks all for taking your time and answering my questions, Very kind of all of you!

[Author]

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