Allotment Growing

Vegetable, Fruit & Herb Gardening

No Dig Gardening

To Dig or not to Dig,

No Dig gardening is a topic that raises its head on a regular basis and seems to offer, at first glance, a way to grow productively without the pain of turning over the land every autumn.

Unfortunately, the concept is generally misunderstood and doesn’t mean ‘gain without pain’!

Conventional Digging

Before looking at the No Dig Method, let’s consider traditional autumn digging. Double digging is where a trench is taken out of the soil one spit deep, and the base of the trench broken up with a fork before incorporating manure or compost and then the next trench is dug with the soil going onto the first. This is great when first taking on land and helps to break up pans or compressed layers below the surface, which will prevent proper drainage.

It also increases the depth of top soil and distributes nutrients making them available to the crops. A ‘spit’ is the depth of the spade, by the way.

Single digging just takes the soil from one spit and turns it over giving some redistribution and breaking up any surface pans. It also buries any annual weeds, which will rot down, but does bring more dormant annual seeds to the surface.

Leaving the soil rough in large clods generates more surface area which water will penetrate and frosts will freeze, breaking up the soil to enable a finer tilth to be achieved in the spring.

It also exposes pests hiding beneath the soil surface to predators, hence the expectant robins watching you and even perching on your spade handle when you take a break.

This method is proven to work and suggested by most conventional gardening books as the way to go.

No Dig Method

As I said earlier, the No Dig Method does not give an easy way out. The concept is better suited to the organic grower who is likely to have a larger worm population. In the autumn any annual weeds are hoed off and perennial weeds dug out, as with the dig method.

Then a thick layer of compost, rotted horse or cow manure, or other organic matter such as leafmould is put onto the surface. This is where the work comes in. To cover 10 square yards with 2 inches of compost will take a minimum of 15 cubic feet of compost. A standard 10 pole allotment would require nearly 17 cubic yards to cover. That is an awful lot of compost! A standard allotment compost bin made from pallets would hold probably hold (if full) 1.5 cubic yards of compost.

In practice it is not quite that bad as you would be liming part of the plot but it is still no easy task.

The mulch over the surface helps to keep the soil warm and, therefore, the worms active, drawing the compost into the ground and incidentally aerating and breaking up the clods for you.

The theory was reported on in some depth by the HDRA in 1967 and the conclusions were interesting. Initially soil fertility was higher, giving better crops, but after 7 years there was a crash and fertility plummeted.

Bob Flowerdew is an exponent of the No Dig Method and claims to have used it successfully for many years without the fertility crash. He contends that the digging required by root crops, especially potatoes, is enough digging and that no more is required.

My conclusions

I grow on a heavy clay soil with an underlying solid clay plan but do have some deep beds with beautiful light soil.

The deep beds are not walked on so the soil hardly compacts and the No Dig Method works. They do get dug as root crops, mainly carrots, are taken and I am sure the great Flowerdew is right.

The heavy clay is a different story. It compacts easily and is definitely much harder to work if not dug. The digging helps the drainage immensely so preventing waterlogging, which is a big problem on our site. One plot on our site is never deep dug, merely hoed and the surface rotovated. In winter it is a covered in puddles, like a paddy field!

Neither can I realistically make enough compost to cope with my needs on a No Dig system. I will continue to dig the most part of my plot each year and take heart from the fact the exercise must be doing me some good!