Soil Preparation
Overview:
Before continuing with this section the writer would like to give the following piece of advice, particularly to those people who are not accustomed to such a manual task as digging.
Faced with a whole new plot to dig, some gardeners may have the urge to get the digging out of the way as soon as possible so that they get on with the planting
This is a commendable attitude but quite often they can over do it and end up injuring their back after the first day.
This injury may render them incapable of digging again for a number of days meaning nothing was gained by over doing it on the first day.
Method:
- The best method of tackling a new plot is to work at a leisurely pace over as many days as is required.
- As a suggestion, dig / prepare one bed per day or half a bed if the going is tough.
- You may find that in the first year, you have insufficient time to dig the whole plot before planting out time.
- This situation may have been brought about by a number of reasons,one of which might be that you could not get access to the plot earlier than you did, another was 'The Weather'
- If this is the case, you could consider leaving the task of digging and do the planting out in areas that you have managed to prepare, then return to the digging after the planting out is completed.
- The task of digging the remaining beds can then be done at a leisurely pace during the rest of the year.
- On completion of the digging it is advisable to cover these beds with black plastic sheeting (or similar).
- This will keep the majority of weeds at bay until such time as you are ready to use the beds.
When to Start Digging:
There is neither a beginning or an end to the vegetable grower's calendar, although it could be argued September / October is the start, as this is the time when preparations normally begin for the following year’s crop.
As good a time as any is to commence digging soon after a crops have been harvested, for example;
circa Week 40* start removing current year’s debris, and finishing off the planting out over wintering crops if not done previously.
Once these tasks are out of the way you are in a position to commence digging the soil and adding humus making material to the cleared areas.
*Some may wait till Spring when the soil begins to warm up and become workable, the choice is down to the individual as to when he/she finds it best to do this preparatory work.
When?
Obviously these preparations are dependant on the weather, the workability of the soil and the soil type.e.g
- The time to dig is when the ground is not so wet that it squelches underfoot, is not frozen or covered in snow.
- Clay / Heavy soils are best dug in late autumn / early winter.
- Leave the surface lumpy for wind and frost to crumble it.
- If the digging is delayed until say, early February the surface should be broken down as finely as possible with spade or fork as the work proceeds.
- Avoid digging and walking on the soil during inclement weather even if this causes a delay in your planning.
- This is particularly important on heavy soils, to do so may compact the soil to such a state as to prevent essential air getting into the ground.
- Light soils can be dealt with at any time.
- If done in late autumn / early winter. the surface should not be fined down unduly.
- This can cause the soil to become hard caked due the action of rain and wind, and may need forking / tilling over again.
- In this case it is sufficient to loosen the surface and remove weeds just prior to planting out time.
Why Dig?
This is open to debate as there are those who advocate a 'no dig' policy is better.
- Basically the 'no dig' method is carried out by mulching / spreading a 2”-3” (50-75mm) layer of organic matter e.g. well rotted manure and / or compost annually on to the surface of the bed.
- The mulch is then left to the action of worms and soil based insect life to pull this mulch downwards into the soil.
- The tunnels formed by the worms provide aeration and drainage and their excretions bind the soil particles together.
- It is said that the no dig system is freer of pests and diseases due to the build up of beneficial soil fungi and insect life.
- Similarly,moisture is retained more efficiently under the mulch than on the open surface of bare soil.
Pros and Cons of the 'No Dig' system:
- This system is easier than digging.
- It is long term process.
- It is reliant upon having a plentiful supply of organic matter.
- It necessary to thoroughly remove any perennial weed roots from the area beforehand.
Pros and Cons of the Digging system:
- It breaks up the soil to a good depth thus making downward path of roots easier.
- Essential air is let into the ground.
- Unused stores of plant food are opened up.
- The soil becomes fertile to a greater depth.
- Plants in deeply dug soil suffer less in dry periods.
- Pernicious weeds are removed as digging proceeds.
- Organic matter is dug in as digging proceeds.
- Organic matter can be left on the surface in the same manner as the no dig mulch.
Where to Start:
- Depending upon the state of the plot, removing debris, turf and or matted weeds is most likely the first task to be tackled.
- If it is Turf, dig up the sods and bury them in the bottom of each trench you dig.
- Do this by laying the sods in the bottom of he trench, grass side down, then chopping them up with the spade.
- If the turf contains grubs such as wireworms or leatherjackets, scatter Lime thickly over the turf before covering it up.
- Alternatively, pare the turf from the surface with a sharp spade used nearly horizontally, before digging begins.
- Place the sods of turf in a heap, grass side down, somewhere on the plot, and leave it for at least year to decay.
- The following year, open out the heap to enable birds to demolish whatever grubs that have survived, and dig it in as though it were manure.
- Some of the fibrous soil created can be sifted for use in seed boxes and flower pots.
- If the plot is covered with weeds such as; Couch Grass, Dandelion, Dock, Thistle, Nettle or any other perennial weeds, then dig these out with a fork.
- On lifting the weeds knock the soil off them and place them in a heap ready for destruction at the next bonfire.
- The resultant ashes are rich in potash and should be forked into the surface a week or two before sowing or planting.
- It is not recommended to use a rotovator with heavily weed infested soil, as all you will succeed in doing is cutting the root systems of these pernicious weeds into thousands of pieces with each piece having the potential to re-root and make the weed situation worse.
- Manual digging and weeding as you proceed will ultimately prove to be the best method of ridding the plot of these pernicious weeds.
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Spade versus Fork - The Pros and Cons:
- Ground that is of a Clayish nature, is more easily worked with Fork than Spade.
- Stony, gravelly or sandy soil needs a Spade.
- Whichever tool is used, it should be of medium weight.
- Smaller tools are better suited to people unaccustomed to digging.
Handling a Spade and Fork:
Please note;
Improper handling of these tools can often lead to blisters forming on hands, and the contracting of back muscles pain, following the guidance in the list below should go a long way to alleviating such problems.
- Stand over the spade (or fork), feet close together, the left foot a little in advance of the right.
- Clasp the Dee/Tee handle loosely with the right hand, the back of the hand facing upwards.
- Grip the shaft about one third down with the left hand, with the back of the hand towards the left knee.
- Keeping the spade / fork as upright as possible, press the blade (or tines of the fork) full depth into the soil with the ball (not the instep) of the left foot.
- Don't jump on it, if necessary, work the blade (or tines) backwards and forwards, maintaining pressure with the left foot, until it has gone down full depth.
- Next, slide the left hand down the handle, remove the foot from the tread of the tool.
- Push downward with the right hand, and lift with the left and raise the bite of soil.
- Then with a twist of the right wrist throw the soil forward and completely over so that it falls upside down.
- After a little practice, those motions will become automatic and the digger will find it quite easy to keep an open trench at his/her feet.
Note: A left-handed digger will naturally reverse these hand and foot positions.
Types of Digging:
Digging; One 'Spit' deep;
A 'spit deep' is the depth of dig equal to the depth of the spade blade or fork tines.
Method;
- Begin digging by excavating a trench approximately 300mm (1ft) wide and one spit deep, across one end of the bed to be dug.
- Place the excavated material in a wheelbarrow or bucket, and cart it to the opposite end of the area being dug.
- When digging successive beds, do not take too large a bite of soil.
- Your own strength, ability and soil type will probably determine what size of bite to take.
- As a guide; push / jab the spade 75-100mm (3"- 4") into the soil at right angles to the open face about a spades width from the edge or previous bite to determine the width of cut.
- Next, place the spade150-200mm (6"-8")back from the face of the cut and push it with the aid of your foot until it has sunk a full spade length (spit) into the soil.
- Ease the spade back towards you to loosen the soil and lift it out and throw the soil forward into the previous cut.
- Finally fill the last cut with the soil you transported from the first cut.
This will be used to fill the last trench.
In practice you will probably find that this task can be executed with a quick jab of the spade into the soil.
Continue in this manner until the bed is completely dug.
Notes;
- If the soil is heavy leave it lumpy and allow the winter weather to break it down.
- Pick out any weeds as work progresses.
- Always keep the spade / fork clean, particularly when the soil is heavy or moist, soil can stick to the digging tool thus making it quite heavy to handle.<
- If manure is being added at this time, place this in each of the trenches formed during the digging and cover it with the soil excavated from successive rows.
- The ideal time for manuring is early winter for heavy soil, and late winter for light soils.
If digging is being done in spring, break the lumps down as finely as possible.
Keep a stick or preformed scraper handy to clean the digging tool as necessary.
Double Digging;
Generally on a plot single digging (1 spit deep) is sufficient, but sometime there is a need to improve the quality of poor, shallow, or badly drained soil and this is where double digging or 'bastard' digging as it is sometimes known, can sometimes help.
Note; This is not a task to be embarked upon lightly, as it will entail a considerable amount of time and effort.
What is 'Double digging ? and how often should it be done?
- Basically 'Double Digging is One spit digging done twice as the names suggests'!
Or put another way;
Single digging done in two layers where the top layer is dug with a spade and the bottom layer with a fork
The result of ground never being dug deeper than one spit deep is the sub soil below becomes so hard packed that the plant roots find it difficult to penetrate it, hence the need to dig two spits deep.
Subject to soil improvements the task may require repeating every three to five years and in other cases never.
Rather than double digging the whole plot at once, consider doing one third of the plot in successive years, and continuing to single dig the remaining two thirds of the plot until the task is complete.
This will result in the whole plot being broken up to the depth of approximately 600mm (2 ft) within three years.
When is the best time to do it?
- At the end of the season, or before the onset of winter, as at this time it should ensure that the ground is workable and is not water logged or frozen.
- It will also allow the excavated area time to settle, and in the case of heavy soil, time for winter frosts to break up clods.
- Having said that, if the area is not in use the work can be carried out at any time.
Method;
- Dig a trench 600mm (2 ft)wide and 300mm (1ft) deep across the bed.
- Transport topsoil to opposite end of bed for use on the last trench.
- Loosen up the subsoil a spit deep with a garden fork.
- Commence Trench two.
- Throw topsoil into first trench.
- Loosen subsoil and add organic matter.
- Adding gravel /grit to the loosened subsoil will improve drainage if deemed necessary.
- Repeat this process in successive trenches to the end of the bed.
- Fill last trench with the topsoil from the first trench.
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Note; always avoid the less fertile subsoil becoming mixed up with any part of the top layer.
Triple or Deep Trenching;
To improve drainage further you could triple dig i.e. Three spits deep!
- Start with a 900mm (3ft) wide trench 1 spit deep, remove and stack topsoil.
- Excavate 600 (2ft) wide trench 1 spit deep in subsoil and stack subsoil.
- Excavate 300mm (1ft) wide trench 1 spit deep in subsoil and dispose of subsoil.
- Fill the bottom trench with rubble and stones to act as land drain.
- Cover rubble with subsoil and organic matter.
- Cover subsoil with topsoil.
Proceed in this manner to the end of the bed.
If you have a problem with 'Poor Drainage' you may; depending upon the contours of your plot, get away with digging just one strip across the lowest end of your plot.
This in effect is simliar to; Digging a land drain, or soak-away to improve the drainage on your whole plot.
Note; Double and Triple digging may not be practical if the Topsoil / Sub-soil is quite shallow and is sitting on bedrock.