Double digging,
A good idea if you have the time and energy.
The idea is to dig 2 "Spits" in depth a "Spit" is the depth of the blade of
your spade, don't worry about it being less than 1 foot.
Yes you take out a trench and put the soil aside, but to make life easier,
if your plot is 20 foot wide then treat it as 2 10 foot plots so put the
soil next to where you take it from. dig up to the end of the plot then back
down the other side. No heavy trucking of soil from one end to the other.
The idea of double digging is to break and pan that may have formed, to
improve the texture of the soil and to give the plant roots a greater depth
of usable soil.
As you dig, skim off any weeds from the top layer with about 2 Inches of
soil, and work this together with any form of humus, Peat, compost, manure,
other annual weeds etc and dig these into the lower spit,
then the top spit is dug to cover the lower dug spit, and so on till you
finish, then just replace the soil that came from the initial trench into
the trench you finish with.
If you are a real glutton for punishment you could even treble dig.
Double digging and treble digging were quite common during Victorian times
when labour was plentiful as was manure. In those days they also used a
system of making "Hot beds by taking out a trench about 4ft wide and 12 to
18 inches deep then building a bed 2ft of so high of fresh stable manure,
and covering it with the soil removed from the trench, this manure would
heat to over 160 F then as it started cooling Glass frames were placed over
the bed and veg plants were planted, the heat from the manure giving the
plants bottom heat and frost protection, so that you could grow things like
lettuce, cucumbers, melons and a wide range of crops out of season.
This form of gardening could use up to 200 tons of manure a year.
Now back to topic. Tilling (Rotavating) is useful for rapid cultivation but
has the drawback of chopping up any perennial weed roots and thus spreading
them , and the blades will cause the soil at the base to form a "Pan" where
the blades rub along the bottom, especially if your ground is clay and is
wet, or even just damp when you work it, so digging is advisable every so
often.
On farms where the ground is "Rotavated" the use things like sub soilers to
break this pan and to help drainage.


--
David Hill
Abacus nurseries
www.abacus-nurseries.co.uk