SOIL: the foundation of life in the garden, rare in our solar system, often taken for granted and a primary reason for the establishment of the B.C. Agriculture Land Reserve - to protect lands rich with life-giving soil.
We are slowly realizing that soil with all of its intricacies, microbial life and resilience is precious, necessary for life and slowly running off into the ocean or blowing away into the atmosphere as a result of poor soil management practices.
There are some people who believe that if you throw fertilizer on the ground, plants will grow. It is true that fertilizer makes plants grow but the growth is soft, predisposed to pest and disease attack and only a short-term fix.
Fertilizer is lifeless and it does not contain bacteria, fungi, worms or the myriad of other soil organisms that comprise a healthy soil. By contrast, when applying organic matter to the soil you are inoculating the soil with microbial life - the true engine of soil fertility.
Improving the soil in our home gardens is quite simple but we insist on looking for the next best gimmick, tool or chemical additive that will boost our soil's fertility.
If you want to enhance your soil's fertility, water less, have fewer pest and disease problems and use fewer additives to grow your garden, start by implementing good soil protection practices. Yes, that means you must mulch the soil to protect it from the ravages of climate and to provide soil organisms with protection and harborage.
Don't like mulch? Then your garden is doomed to be weak, high maintenance and hooked on fertilizer in a perpetual cycle of addiction and decline that . . . sorry, I digress.
Mulch should be maintained on the soil's surface year round to a depth of seven to 10 centimetres. Never dig your mulch in, only replenish it when it wears thin. Thinning mulch means the mulch has been digested by soil organisms and is feeding the plants.
The practice of applying bark mulch, leaves or straw to garden beds in the fall and digging it into the soil in spring is not a healthy practice for the residential garden. In fact, digging in uncomposted materials is not recommended, to avoid a nitrogen loss from the soil caused by soil bacteria that break down such materials by using soil nitrogen for food-energy to break down the material. The more the bacteria use, the less there is available for plants.
The second reason not to dig uncomposted materials into the soil is to prevent offgassing of ammonia and other gases that are released as part of normal decomposition, and those gasses can be damaging to plant roots and soil organisms. So, always compost green waste, raw leaves, household food scraps and so forth before they are dug into the soil.
To improve poor soil, there are several practices that can be easily implemented.
Firstly, always dig deep when planting or amending the soil. The deeper the soil, the deeper plant roots can grow.
Tree roots have been shown to root down beyond the normal one-metre average depth to as far down as 80 metres in areas where the soil is deep. And Prairie perennials have been shown to have roots extending 1.8 metres into soils that are undisturbed and old.
Deep plant roots are better able to withstand climatic stress like freezing and drought. Deep soil also allows a larger population of microbial life to grow and the more soil life you have the healthier your plants will be.
Secondly, amend poor soils with organic matter like manure or compost, which are antibiotic, microbially active and structure building. Fertilizer, by comparison, lasts a few weeks and its residue leaches into the ocean, creating dead zones. There are several dead zones in the ocean around the world caused by fertilizer leachate running off from agricultural operations like the one off the coast of Oregon and in the Sea of Cortez off Mexico, and probably in the Georgia Straight off Vancouver.
Organic matter may not be practical for large agricultural operations but it is ideal for residential soils and it's available, inexpensive and digging it in gives you a full body workout. Be sure to dig in the amendment thoroughly to provide a consistently amended soil profile and do not break soil lumps for uniformity. Healthy soils have diversely sized particles that create spaces to allow air and water to move throughout.
There is another important way to protect and improve soil in the garden: leave it alone. Old soil is not dead, degraded or lifeless unless it has been left unprotected or abused. Healthy soil requires a long time to grow microbial life and a physical structure that is conducive to healthy plant growth. So dig deep, have no bare earth and hug your soil.
Todd Major is a journeyman horticulturist, garden designer, writer, consultant and organic advocate. For advice contact him at [email protected].
