Soil Cultivation – Tips for Consolidation of Garden Soil

It is often said that you can recognise policemen and gardeners by the size of their feet. Whether the job produces the size of feet or whether people with large feet became gardeners and policemen I have never found out, but whether feet are large or small they are certainly most useful to the gardener.

Not only do the feet help, but the footwear helps too. The broader the footwear the better, and in some cases it is desirable to increase this by strapping boards under the soles to avoid over consolidation. Nowadays these are seldom used.

To me however, consolidation is neglected in so many instances today and I invite those new to vegetable growing to consider this  aspect. It is the introduction and use of motorised cultivators and rotavators which make consolidation more essential, particularly in the vegetable garden.  I have seen ‘gardeners’ walk over newly rotavated soil and sink up to their ankles and then wonder why on earth they cannot grow good-hearted cabbages and firm sprouts. Possibly not one gardener in ten thousand these days would ever dream of dragging a roller over the vegetable plot, but it would certainly do much more good there than on the lawn.

I remember long ago, watching my father and many of his age group, preparing soil for the onion bed, for lawns and for brassica crops, side stepping literally for hours backwards and forwards across the garden. I have filled in many hours like this myself preparing ground for crops which require a firm soil. When preparing stations for individual rows of sprouts on recently cultivated or dug soil, the technique of using 9 inch planks and running the roller up and down the planks seems to be a thing of the past. But after this treatment we certainly got good sprouts.

In my experience, consolidating the soil, particularly for certain crops which enjoy firm soil conditions, is just as important as digging, aerating and breaking up soil clods. What is also not generally appreciated is that large quantities of partially decayed compost or manure which have been dug in, will further decay after being attacked by bacteria and fungi and will leave the soil spongy. This means that even where soil has been trampled down hard it will still be honeycombed with air spaces after the material has rotted.  Without consolidation, roots will wander into cavities and dry up as they grow faster than the soil settles naturally by the action of rain and so they never get a good grip on the soil.

Similarly when roses, trees and bushes are planted, it is always recommended and should be the accepted practice that they should be trodden in firmly. If a fair amount of organic matter such as peat is used it is even more important to firm the soil thoroughly without paddling down the top surface.

There are several reasons why garden soil, particularly in the vegetable garden, is not consolidated as was the practice a generation or more ago.

  • One is that often unsuitable garden footwear is used, light shoes with thin soles or the best wellington boots, instead of thick heavy boots.
  • The time factor also enters into it – everybody is in a hurry to get the job done – and the wide use of mechanical cultivators doesn’t help. There is nothing wrong with these but the rapid rotary movement of tines and blades pulverises the soil whilst it mixes in the manure.

But either the soil must be allowed to settle by  itself naturally, which takes several weeks or even months, or this process must be accelerated by rolling or treading.

Two crops especially spring to mind as examples where consolidation pays off; sprouts, which if planted in loose puffy soil tend to topple over or produce blown sprouts instead of tight buttons, and tomatoes. With the latter, the fruit becomes large and distorted with heavy crops of leaves on gross coarse plants. By consolidating the soil the fruits are of even shape and size with smaller leaves and fewer side shoots.

After any firming, always lightly loosen up the soil surface, for over consolidation can be equally as harmful as loose soil. This can often occur when the soil is very wet. Again this depends on the composition of the soil.

Soil Types

soil types

Roughly, soil types fall into three main groups:

1.  Silt, where the soil particles are extremely fine;

2.  clays where the particles are still very line but not so fine as silt; and

3.  sandy soils where the individual grains are much larger.

As a rule the sandy soils cannot be over compacted either when wet or dry, but silts and clays are very susceptible to compaction when wet, especially if they are short of organic matter.  This was brought home to me when visiting a nursery where a lot of treading had taken place between the rows of plants. When the crops were lifted, water was standing in every deep footprint and wheel track and yet the soil beneath was extremely dry. This was a classic case of surface soil puddling.

This is one of the worst features of house building in the winter time or following heavy rain. The soil around the house, even if it is of reasonable texture before the builders start, can be damaged for several years. It is made worse when the excavated soil from the bottoms of trenches is left on the surface and compacted by many feet or by the wheels of vehicles. Where this has happened it is not advisable to dig the area, because by turning the floating or puddled material to the bottom, it could lay for many years forming a barrier to root penetration and water seepage. Far better to fork up the top 3 inches and leave this exposed to the ameliorating effects of frost and winds or, in the springtime, to showers and sunshine. Of course, this may delay the preparation of the garden but it is well worthwhile, especially if there is a lawn to be laid.

Even if the climate is ideal for working, the soil conditions may be completely unsuitable and it is better to leave it until they improve. This can even happen when there are pruning jobs to be done, for after paddling around a tree, both feet and soil can be in a right mess. Under such circumstances it is better to spread a few thick sacks on which to walk to spread the weight and to prevent this puddling of the surface soil. I use 2 inch plastic mesh fencing. You can also get too much consolidation when treading in trees and shrubs at planting time when the soil is ‘plastic’.

You may have noticed that deep footmarks made on wet soil will fill up with water which may remain there for days or even  weeks. As a result, in extreme cases, green algae may form in these deep indented footmarks. This can happen, too, amongst rose trees when shortening them back in late autumn or early winter. When working in such conditions it pays either to wear boards on one’s feet or to make short portable duck boards about 4 ft long and 18 inches wide. I find that two of these made of 3 inch lathes with 2 inch spacing are easier to manoeuvre and better to use than planks.

Certainly no wheeling of a narrow-wheeled barrow should be done over grass when it is extremely sodden. Wheel barrows with an inflatable tyre are far better, but of course not everyone has this more expensive type. If any wheeling must be done on the lawn, then either planks or plastic mesh should be laid down first. I keep a roll of 2 inch plastic mesh for this purpose – the type that is usually sold for training clematis. Incidentally, if you employ this technique, unroll the netting and then turn it over against its curl. The ends can be secured by two bamboo canes pushed into the ground so that the mesh is kept taut.


31. July 2010 by Dave Pinkney
Categories: Manures and Fertilisers, Soil Cultivation | Tags: | Comments Off on Soil Cultivation – Tips for Consolidation of Garden Soil


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