soilless growth medium contents

4 july 2012

I 've just got a reply for my request to Suttons about the contents of their ready made all in one soilless growth medium



I suspect it will be similar to most other UK products of a similar name in that there is no composted manures or vegetable matter ....... it is a chemical factory formula that ensures consistncy of chemical based nutrients with nothing natural in it other than the peat & sods of grass in soil .



This is per 100 cubic litres .



The compost contains the following:-

90% peat and 10% sod.

1.1 kg base fertilizer 14-16-18 + trace elements

25 litres medium Vermiculite

4.5kg lime


[size=9]I hope this response is helpful to you.


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I know it' early and I'm out of my region again. I looked at the contents, an I have a question, or two.

Is this a base for what they put in it? 90% peat and 10% sod.

Isn't sod a grass and dirt(soil) product, it is over here.

1.1 kg base fertilizer 14-16-18 + trace elements

25 litres medium Vermiculite

4.5kg lime

It is the entire base produce plus the chemicals .

Yes sod can be a product on it's own ....... but where do you draw a line to clasify it ?

In a three inch thick sod/turf or 1 inch thick sod /turf the decayed vegatation content will vary tremendously .

But over all in the finished mix I feel the decayed vegetable matter will be almost certaily in the less than 3% once you take the sand & clays out the sod /turf .

At school well over 50 years ago we used to make our own composts to the John Innes formula by cooking a soil based mix in a sterilizer/ oven in the rural science lessons .

In the general science lessons we took samples of the finished product and separated them it in water & spirits , after drying the residues we then calculate the percentages by weight and volume and measured the nutrients content wrt NPK.

This was done to make sure that what we had produced was indeed the real Mc Coy , as we were doing almost ground breaking mist propagation experiments on heated beds for the biology angle of our sciences & bring in the mathematics as an integrated / reinforced subject.

Next time you get hold of some commercial potting material , put a couple of inches of it in a tall jar , 3/4 fill with warm water , put the lid on and shake like mad several times over a day. Then set it down where it will not be disturbed so it can settle .

Initially after a few hours you should soon see different levels of sediments settling . Get a metric ruler or one in one hundreths of an inch and measure the thicknes of each band colour . leave it severla days completely undisturbed and bands of colour /different materials will appear .

Run your measurements /checks from pebbles , grit ,coarse grit, fine grit , sand , fine sand , coarse silt , fine silt and the several bands of vegetion that you see , then work them out as percentages of the whole original height of the matter you put in the jar before you put it to settle .

It is a good experiment to show kids that dirt is a complex matter & bring in simple mathematics that are applicable to every day life but makes it more interesting .

I've just re read the email ..

I estimate 70 % or so content of the final product will be peat and sod product add in the 25% vermiculite equals 95% assume 5% for the remainder ...

That would work out at about 63% peat and 6 % sod content for the final mix ...

Does that sound right or am I having a seniors moment a few weeks early

Is that what you were after ???