Monday, 30 June 2008

Old Soot Secrets

Following a plea for soot advice from aged tomes by Flange member VP I can provide this from The New Illustrated Gardening Encyclopedia by Richard Sudell, F.I.L.A., A.R.H.S., (the book is not dated but the inscription is 1932).

"There are 3 reasons why soot is valuable to the gardener: it contains a little nitrogen; it is a good insecticide; it darkens the soil surface, and therefore makes the soul warmer by retaining solar heat. Soot should always be stored dry and can be used in making liquid manure, or as a surface dressing along the rows of growing crops, either alone, or mixed with lime. If mixed with lime it makes the best insecticide, as the fumes are objectionable to insects of all kinds."

He also has a diagram (see pic) to show how to make soot-water - a sack full of soot, plus a brick to keep it submerged, hung from a rope in a butt of rainwater - with light excluded.

Practical Home Gardening Illustrated (1949) by the same author adds no more information but does include a very similar diagram in the month of March. The diagram bears the legend "Soot water stimulates pot plants", and I'm unclear whether March is time to make, or to apply soot water.

It does have rather lovely pictures inside the cover of Garden Friends & Foes which I’ve posted for purely gratuitous reasons.
My copy of The Complete Gardener first published 1950 (and heavily reprinted) by W.E. Sherwell-Cooper (a man with a formidable array of credentials after his name) has this -

"Soot is a nitrogenous manure which darkens soils and so enables them to absorb and retain heat better. More generally used as a top dressing in the spring. Suitable chiefly for all members of the cabbage family. Usually applied at 5ozs. to the square yard."


VP said...

Thank you GM - I love the illustrations so you were right to show them :) Makes me want to go and rootle around in 2nd hand bookshops right now.

I think the old boys up at the allotment are using soot primarily as a soil warmer owing to our heavy clay. Fred also told me about its supposed slug repelling properties at one point. Must go and ask them too.

This soot tea stuff is new to me though - must have been what MR was going on about!

I'm still drawing a blank on whether there's heavy metals in there, never mind dioxins. I'm quite sure where it fits into an (almost) organic regime either. There's also conflicting info on whether it's acid or alkaline - will take my trusty pH meter up there and find out!

BTW - I'm not turning into MR - this is all in the cause of scientific evaluation!

patientgardener said...

I found some more info late last night but left it at home and am at work at the mo. I was going to do a post on the uses of soot but you have beaten me to it. Basically the book I have says use soot for detering very pests from your vegies. I will do a post this evening about it - just for VP

VP said...

Oops - left out the not in 'not quite sure where it fits in an organic (almost) regime'

And Patient Gardener - a post especially for me? Thank you :)

emmat said...

VP=MR ha ha

VP said...

I now have my very own soot book! Hubby has come back from Darlington with his parents' stash of post war gardening books :)

They're brilliant as they were actually written during the war so there's a breathless, digging for victory style about them.

Will bring you more details and photos shortly!

Anonymous said...


Your soot is likely to contain heavy metals. The only sure way of knowing would be to send it to a lab to be tested, whatever the pH.

Any soot that has been collected in a large quantity is likely to have come from some kind of industrial source. ie it's a waste product containing all of the rubbish extracted in whatever process was carried out.

Wouldn't recommend using it to grow vegetables for consumption, however much it imporves the soil.

There's probably a very good reason why pesties don't go near it and they likely aren't thinking of their carbon footprint.

jac said...

we have a dustbin full of soot from a coal and wood fire, would it be beificial to our veggie/ flower garden and how.

The Garden Monkey said...


I would read the comment before yours - which I agree with - and not use it on veg, but I am going to do a post on my main blog about it, to ask for other peopel's opinion.


tkn said...

how is soot nitrogenous? soot is nearly pure carbon.
I know its hard to clean off of pots