Across Canada this week we?ll all be doing the same thing: getting down and dirty in the garden, digging, planting and dividing. Spring activities that bring joy to the heart but are killers for the old knees. This is definitely the time to do serious stretching exercises before getting on with these chores.

As any accomplished gardener will tell you, understanding the nature of soil is one of the first principles of good gardening. Quite often we forget about it in the urge to get the newest and most interesting plants or just struggling with getting started.

I love digging in the earth, to feel part of this vital, living thing. We know so little about this basic stuff of our survival that it?s breathtaking we can be so casual about it. There are many types of soil: sandy, clay, loam, acidic or alkaline just as starters. It?s filled with literally billions of minute forms of life from fungi, to bacteria, to protozoans to the more familiar animals such as worms and the usual creepy crawlers.

Each of these creatures has a function to play in the health of the soil. Like all other parts of the biosphere it?s exquisitely interconnected. Usually, when we interfere with this process we aren?t doing any good. But that doesn?t mean we don?t have a role in improving soil or keeping it in good condition.

The most important element in the soil is humus. This is the dark stuff full of nutrients where most of the soil activity takes place. All humus is organic matter but not all organic matter is humus. Humus is organic matter that?s gone through some form of decomposition. Manure, leaves and kitchen detritus for instance, though they are organic matter haven?t reached the humus stage yet.

Adding organic matter to the soil on a regular basis will lead to building up new humus releasing nutrients (called mineralization) as it breaks down. Mineralization takes place when there is aeration, moisture and balanced mineral nutrients. Compost is one of the ideal ways of adding organic matter that?s decomposing. It doesn?t take a lot to maintain good soil.

If you are starting brand new beds, dig down a minimum of 30 cm and mix in some organic matter such as compost or manure. This will help out developing root systems to withstand just about anything dished out to them.

But I?m a great believer in not disturbing the soil once plants are established. I don?t scrape around or dig anything into the soil around them preferring to lay compost and mulch around them instead. This top dressing may seem like a lazy way of doing things but it also means that fine roots systems and complex soil structures aren?t agitated. The vital life of the soil is left alone to carry on doing the job nature intended. Every time I put shovel to ground, I have this image of millions of beings dislocated.

In our neighbourhood we?ve developed a spring habit of ordering yards of triple mix and splitting the cost. Don?t do this without an excellent supplier. You might get stuff that?s been scraped out of corn fields and laden with chemicals or filled with weed seeds. It could be a disaster. Ours is the good stuff and I just lay the new soil in spots that need some bumping up where it?s absorbed like magic.

If you?ve just moved into a new housing development chances are that the builder has carted off your topsoil (probably to sell to us) and left you with a disgusting mess of subsoil disguised with sand and covered with sod. It will die within a year. So get out there, start digging and add masses of organic material to it. It will take a few years to recover but better to do this now than face the disappointment of having nothing grow. If you have a large plot, start with pockets and slowly develop the garden. You can help out the struggles of the rest of the garden by adding lots of compost to the surface and let the worms do the rest.

Think about the complexity of soil and its mysterious ways the next time you are tempted to dump a pile of fertilizer around your plants. Do they really need it or would a handful of compost be a better idea?