One year on from Cutting out Commercial Fertiliser

September 2017

I’m keen to do an update on the series of blogs I wrote last Spring when I decided to stop using commercial fertilizer, no matter how good it was, and build my skills and confidence that I could do it using my own local resources. I still feel very happy that I did use them for the first five years, I wouldn’t be in the situation I am now if I hadn’t.

Basically I began gardening my current garden six years ago.

We began with a sandy pumice based soil, with

  • a humus content of 4%
  • a cation exchange capacity C.E.C., of 7
  • Available Calcium level of 200 kgs per hectare ( it has to be up around 2-5,00 kgs per hectare to sustain beneficial microbial cycling!!
  • Available Phosphate 53 kgs per hectare, with a P:K ratio of .2

Basically by using Environmental Fertilisers products, getting really good at making high quality compost, by adding clay to raise the cation exchange capacity and biochar more recently we built our

  • humus up to 20%
  • available calcium up to around 2,4000 kgs per hectare with an available C:Mg ratio of 6.4. ( pretty good)
  • available phosphate up to 52 kgs per hectare with a P:K ratio of .1 ( no where near good enough)

So at that point I decided enough is enough.. we know we can build soil by bringing minerals etc in…. but can we maintain it from there and even keep building it using our own resources or very local ones .

I have to say I was nervous….. I don’t know any body who is doing it, and I wanted very much to keep building my soil and food quality… and I was doing it publicly

At this point I stopped using EF products in my home garden.

Over the past year I have used only my own compost made according to instructions in The Art of Composting, (without any brought products as inputs into the compost) plus our own urine applied onto the soil every week at 2 lt of urine to 7 litres of water, and our own humanure composted for 12 months first which means none has gone on yet. (Check out this wonderful booklet with info on using urine and humanure )

Last Spring we used my own liquid fertiliser mixes recipes here as well. Up until the winter garden went in everything looked great. We then applied 5 kgs of Biochar per sq m of garden bed last Autumn as a potential way of upping the CEC enabling the soil to hold more minerals moisture and microbes. The biochar was mostly our own charged with urine, but we didn’t have enough so used charged EF biochar . The Winter garden did not grow well.

I now have a new Reams soil test (available at BioServices 1 Railway St Paeroa) , and that shows us why the Winter garden didn’t do well , and other things!

I was waiting with baited breath for the new soil test and I’m super excited now to be able to say that using the above inputs has held the humus level, held the nutrient levels (Except the available calcium I’ll talk about soon) Most critically upped the phosphate and the P:K ratio considerably. This has to be the urine. Urine contains significant levels of plant available phosphate. The calcium levels however were not looking good and that is obviously why the Winter garden did not grow well. The biochar had grabbed all the plant available calcium which is largely what biochar does. Grabs everything until it is fully charged.. obviously it wasn’t totally charged. We have now added calcium, I used lime flour from Farmlands because I wanted it to go on fast and get grabbed up by the biochar in the soil until that was fully charged and then be available to plant growth. Grant worked out that we need ½ kg per sq m. That has totally turned things around, and the garden is now humming. I’m sure the C:Mg ratio will be back balanced at 7:1 ( with Calcium levels up around 3,000 or more) and with the P:K ratio also far better our Brix’s this Summer will be higher than ever before. They are right now from 16—-22 before the sun even gets high in the sky!!

I will do another Melich test soon to find out what the CEC is these days but it sure is very different to what it was. It doesn’t even look like the same soil. Or act like it.

. …

I would have to say that yes, I’m now confident we can grow soil and nutrient dense food with out commercial fertiliser ( possibly with the exception of locally produced lime to get levels up to begin with) but what I don’t know is how many years or generations it would take if we don’t use them in the short term. At this point I would still say that using them saved me maybe 20 years of having poor quality food or more. Using these products means I can now do it myself… super empowering stuff.