IMPROVING SOILS (PART 2): ORGANIC MATTER
The best time to improve your soil is prior to planting.
Working around existing plants is less effective and care must be taken to not damage their root systems. It’s best not to incorporate amendments within the drip line (i.e. the outer edge of canopy) of younger plants. Improving the soil near mature plants should be limited to spring so they have time to recover from possible root injury.
Adding organic soil amendments such as compost, peat moss, alfalfa pellets and composted manures greatly improves productivity.
As organic matter breaks down, it releases nutrients and improves the physical structure of the soil, increasing its aeration, drainage, nutrient and water holding capacity, and more importantly from a gardener’s perspective, its workability. It also improves the environment for soil microorganisms, which play a critical role in decomposition and disease control.
Organic matter breaks down into humus that hold potassium, calcium, magnesium and hydrogen in the soil water in a form readily available to plants. It also holds almost twice as much water as clay.
COMPOST
Compost consists of garden and kitchen waste on their way to becoming humus. Ideally, composting speeds up an otherwise natural process by providing ideal water and air conditions for decomposition. The end product is an excellent soil conditioner and slow release fertilizer that would otherwise be lost forever in garbage dumps and landfills. Note: visit saskatoon.ca/services-residents/waste-recycling/ composting for home composting tips.
MANURES AND OTHER ANIMAL BY-PRODUCTS
Manures may be less available in urban areas and they take a bit more effort to spread. Their nitrogen content decreases with age and exposure to wind and rain. If bedding and litter is mixed with manure, it will contain less nitrogen but more organic matter. Fresh manure is high in ammonia and salts and can be detrimental to plant growth. It should be allowed to age or compost for at least a year prior to using. Composting allows the ammonia to dissipate into the air and the salts to be leached out by rain. In addition, the composting manure should heat up (hopefully) high enough to kill weed seeds.
Manures vary in their nutrient content depending on diet, the type of animal and storage conditions. Commercially dried manure is easier to spread but more expensive. Slaughterhouse by-products such as blood meal, bone meal and horn and hoof meal contain a higher concentration of nutrients but less organic matter. These products are more expensive and less available than they once were, as many have been diverted into animal feeds.
PEAT MOSS
Peat moss can hold 10 to 15 times its weight in water. Interestingly, it contains a compound called shagnol that has antiseptic properties and was used in wound dressings during the First World War. Long used as a fuel in Europe, peat moss was only first used for horticulture a century ago.
Although low in nutrients (about three per cent nitrogen), peat moss increases the soil’s ability to hold nutrients and water and adds organic matter to the soil. Because its ph is between 3.0 and 4.5, it is useful in lowering the ph of soils for acid-loving fruit such as blueberries and lingonberries — but you’ll need a lot and it is not a permanent fix.
ALFALFA PELLETS
Composed of dehydrated alfalfa forage, alfalfa pellets have a high fibre content and contain more than 20 micro- and macronutrients as well as naturally occurring plant hormones. They have a high moisture-holding capacity (four times their weight), a neutral ph and are easy to spread.