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Getting into Shape

soilgardenBeginning a garden can be as simple as chipping off some grass and turning over the soil with a spade. Or, depending on what kind of soil you’ve got to work with, it can involve quite a lot more work. The big question, especially for beginning gardeners, is: ‘How do I know what sort of soil I’m dealing with?’

Some people lack the confidence to have a poke around for themselves to check out the potential of their chosen garden site, and prefer to send off soil to be tested professionally. But in my experience, unless you suspect your soil has been chemically polluted (not something an eye-check can easily tell you) assessing the garden site isn’t difficult. All it involves are a couple of simple tests which you can manage yourself, at home.

Compaction test

This is one test where number 8 wire comes into its own in a new kind of way. Take a meter long piece of number eight wire and push it firmly into the ground. Take note of when the wire bends. If it slides easily into the soil to a depth of around .3 of a metre, that’s a good sign. If it bends sooner than that, it means your soil is compacted (packed down hard). Water can’t penetrate into soil that’s this compacted, and plants’ roots will have a job growing through it. But all is not lost. Compaction simply means you’ll need to ‘work’ your soil more, digging down at least a spade’s depth to loosen the ground, then chopping up the clods. Interestingly, farmers measure the workability of their soil by monitoring how much fuel their tractors use to do the job. Perhaps you’ll be able to judge the workability of your soil by the amount of sweat that collects on your brow as you dig, and the quantity of dinner you consume after the job is done!

Soil structure

Have you ever watered a pot plant (usually one which hasn’t been repotted for a long time) and noticed how the water just flows right through the soil and out again? The reason for this failure to absorb water is that the soil has little structure; it has virtually nothing in it to absorb the moisture and hold it until the plant’s root have time to make use of it. It’s exactly the sort of soil you don’t want in your edible beds.

The best kind of soil for a food-growing garden contains crumbs (soil scientists call them ‘aggregates’) of different shapes. Rounded crumbs have loads of ‘porosity’ which simply means water quickly runs around them, helping the soil to drain well and not become too gluggy (your pot plant in-need-of-repotting has too many rounded crumbs). But good soil also contains crumbs of organic matter (tiny pieces of broken down plant material) which are absorbent and good at holding in moisture so it doesn’t drain away too quickly.

How do you know what kind of soil structure you’re dealing with? The answer is simple. Scoop up a hand full of dirt and squeeze it firmly. If it holds its shape loosely (as opposed to clay which holds its shape solidly or sand which doesn’t hold its shape at all) you’re in luck. Adding organic matter (compost is best for this but lawn clippings, decaying leaves and rotting straw all work well) will soon help soil hold onto moisture for as long as it needs to. Adding fine river sand to soil will help with drainage.

After a year or two of working hard in your garden to loosen up soil and improve its structure, your edible beds will be in great shape – and so will you!