Garden School:


Garden School:
Teaching this week: Rose pruning (as always!) and leaf mold.

Friday, 28 December 2012

Double Digging: don't do it!

I was given a book for Christmas: called, intriguingly, The BAD tempered Gardener" by Anne Wareham.

It seemed like a whimsical play of words on Christopher Lloyd's book about the Well-tempered garden, and seems to be written by a lady who genuinely loves gardening, but at the same time, really, really hates it. She loves the effect, but hates the hard work involved.  You should hear her on the subject of double digging!

Mind you, you should hear me on the subject: summed up by the phrase "Nope."  I don't do double-digging: in my opinion it is one of those exploded myths, that has been scientifically proven to be a waste of time, but which people still seem to torture themselves with.

What is double digging?  Oh, it's horrible - you start at one end of a plot, generally a vegetable plot of the old-fashioned large allotment size. You dig out the first strip to a depth of one foot deep, putting the soil onto a piece of plastic or into a wheelbarrow. This leaves you with a trench. You then fork over the bottom of this trench to loosen the soil, and add some manure.You then dig the second strip, turning the soil over into the first trench. Thus creating a second trench. Whose bottom you then fork over, and add manure. You then dig the third strip, flipping the soil into the second trench. And so on. When you reach the end, you trundle round the soil from the first strip, and tip it into your final trench.

Simple, huh?

No mention of the fact that more than one spit deep, your soil turns into solid blue clay that weighs a ton, breaks your back, refuses to slide off the spade, and when scraped off with a stick, lies there as though awaiting the potters wheel, looking about as far from "fine tilth" as it is possible to get.

No mention of the fact that all your decent topsoil is therefore buried under a layer of clag, stones and whatnot, leaving cracks and lumps in equal numbers.

Nor any mention of the fact that you are unable to plant anything into this mess for several months, until the top layer has weathered down a bit, to the point where it becomes possible to break it up into clods.

Nope! As I say, "exploded theory", it is now accepted that double digging ruins the soil structure, destroys all those lovely interactive eco-systems of worms, beetles etc, and does not bring new vitamins and minerals to the surface. It's what I call "received wisdom" which is also known as "blindly doing what you were told to do, even though there are patently better ways of doing it."

OK, on soil that has been badly compacted over many years, ie under mown grass, or on a new build site, then you would need to aerate the soil - but frankly,  in either of those situations I would seriously consider hiring a chap with a rotavator. Or just tipping compost on the top and letting the worms get on with it. Or planting spuds, and letting them loosen it up. There are many options other than double digging, and there are very few instances where double digging is the right and only thing to do.

Let me tell you a story about the Sunday roast.  It's a joke, ok, not a true story:

Newly married husband compliments wife on her Sunday roast. "Mmm, very tender" he says. "Glad you enjoyed it," she responds, "Roasts are dead easy, your turn next week." (it's a proper, modern, marriage.)

Next week, his turn to cook the roast: being less good at cooking than her (give him time, he'll learn) he asks advice on several points, and is reminded to cut off the end of the roast before putting it in the oven.

"Why?" he asks.
"To make it tender" she replies.

Afterwards, being of an enquiring turn of mind, he is thinking about this issue. "Why, exactly, should cutting off the end make it more tender?" he asks. "Dunno," she says, "I've always done it." Continued discussion leads to the fact that it was her mother who taught her to do this.

They visit the mother and ask her.

"Oh, yes," replies the mother, "Always cut the end off the joint, makes it tender, always done it." Cross-examination leads to the fact the it was her own mother, in turn, who taught her this.

They rush off to the nursing home and find the ancient grandmother. When asked why she taught her daughter to cut the end of the roast off, she replied "so it would fit in the dish, of course."

There you go, the classic demonstration of  Received Wisdom: doing it a certain way because it has always been done a certain way, without ever asking why... or whether it can be done better, faster, easier, some other way.

In gardening, you should always challenge Received Wisdom. It's easy - and after all, it's not as though gardening were something vital like open heart surgery, which is clearly a sphere in which you definitely would stick to the Received Wisdom: "shall I cut this artery open before I clamp it? Hmm, everyone says you should clamp first, cut second. Guess I'll do what everyone else does, in this case. "

No, unlike surgery, gardening is a field in which mistakes, in the biggest sense of the word, really don't matter very much. The worst you are likely to do is kill a plant or two. But you might make some really useful discoveries.

As a point of interest, SmugAmanda used to boast about her mass bulb planting style: she would lift an area of turf, scrape out some of the soil below, scatter a handful of bulbs and press the turf back down on top. No time wasted setting the bulb the "right" way up - she would just dump them in, and bury them. Saved her hours of time, considerable backache, and the results were 100%  flowering, regardless of which way up the bulbs were.

Now, any gardener can tell you about bulbs that have been found upside down but still sprouting beautifully, I know that I've found a few over the years.  But not all that many... I also know that many bulbs have contractile roots with which they pull themselves deeper into the soil, so it's not too much of a stretch to imagine that some bulbs are capable of "turning" themselves right side up in the soil.

So SmugAmanda was right in her slapdash planting style - it really doesn't matter about "setting" the bulbs beautifully upright.

A good example of a time when ignoring Received Wisdom was the right thing to do. Refusing to double dig is, I feel, another good example.  Taken to extremes, you get the "no dig" veg garden system, whereby you use heavy planks or sleepers to create small, accessible raised beds, fill them with good soil,  plant your veg,  and never, ever have to dig them over. Just weed out the weeds, lift out the produce, gently fork over with a hand-tool, or rake it level, and re-sow.

The trick is to get the beds sufficiently narrow that you can reach to the centre from each side, so you don't need to tread on it to weed or harvest. If it never gets compressed by your big gardening boots, then it never needs to be dug over, just "fluffed up" as necessary.

All of which is a long way from reviewing a book, but very much in the spirit of it!

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