TO DIG OR NOT TO DIG
To dig or not to dig, that is the question, or is this a spade I see before me.
One of the big debates in horticulture at present is the question of whether it is better to dig, or not to dig our plots. Some gardeners are quiet evangelical in the call for no digging, saying that digging upsets the soil structure and that no dig/no till saves time, gives bigger harvests, is ecologically beneficial and keeps carbon in the soil.
Against this, diggers will say that digging the soil will improve the structure of the soil as it reduces soil compaction and improves soil aeration. The effect of this is that there is more oxygen available to the plant roots and the water drainage is improved. It also makes it easier for plant roots to penetrate and ‘reach out’ further into the soil. Plus it makes it easier to sow seeds and plant out seedlings.
When the RHS visited our Society last year I asked Guy Barter, who is the RHS Chief Horticultural Officer, whether he was dig or no dig, and he said that farmers have been ploughing fields for centuries and that he couldn’t see anything wrong with digging.
But I guess we all been swayed by the present wave towards no digging. Monty has talked about the virtues, plus Beechgrove Garden have recently run successful trials.
The guru of no digging in the UK is Charles Dowding who has been practising no dig for nearly forty year and has been trying to spread the word though his books, his youtube channel, and his courses at his garden in Somerset.
Watching his videos it is easy to be persuaded, with his calm soothing voice and easy manner – he could even sell me a second hand car. And certainly his results in terms of harvest are highly impressive. His potato harvest video earlier this year showed yield that was staggering.
But, but, but it seems to me that at the centre of his method is that he says we must spread a two inch covering of compost over our soil each year, which for me begs the question of whether it’s no dig that achieves the yield, or is it the annual compost covering.
And the problem of annually covering the plot with compost is where do we get that amount of compost. I have three compost bins, each roughly a cubic metre in size. Each gets continually filled throughout the year, but when it all gets composted down it gives me at best half the volume in compost i.e. one and a half cubic metres. My calculator tells me that one and half metres spread two inches deep achieves approximately thirty square metres – and a 5 rod plot is approximately 125 square metres – so it will only cover a quarter of the plot.
I haven’t seen Charles Dowding directly address this problem –he has mentioned “well rotted” horse manure, mushroom compost, and buying compost from the council i.e. council made compost. There are problems in all of these for us. The horse manure which we get delivered can be well rotted in part, but there’s a lot of straw, string, clay, and even silver spoons to content with. And how can we get mushroom compost and council compost in the quantities that are needed to give a two inch mulch?
Another problem with “home made” compost is that unless we invest a lot, and I mean a lot, of time in properly treating the green waste by chopping it down and taking out all the hard pieces in order to achieve the necessary temperature in the heap, the resultant compost will still have a hell of a lot of seeds in it – necessitating constant hoeing.
So it’s pay your money and take your pick. What do I do? Firstly, after the initial double dig having taken over a plot that’s it – after that it’s tilling with a rotivator. Secondly, after about three years I’m stopping tilling and covering with compost - my own made, plus spent multipurpose, plus horse manure. It’s up to over a quarter of my plot size at present – so 5 rods out of 20. In a few years it will be much more, but for how long I will have the energy to spread 20 rods with compost each year I don’t know.
So, is it much ado about nothing, or will it be all’s well that ends well?