Soil Building

An amazing amount of bacteria, earthworms, fungi, and micro organisms can be found in healthy, rich, organic soil. They release nutrients that the plants then access for food and nutrition.

Look below for more information on soil building basics, mulches, and DIY organic fertilizers including good ol’ compost, coffee grinds, manure, and seaweed.


Soil Building Basics

Soil can make or break your gardening season.

This is because it needs to contain the the nutrients required to sustain plant life. While different plants require more or less of these nutrients, every garden needs you to put back what you are taking out.

Generally you are looking to have loamy soil, which contains the perfect balance of sand, silt, and clay (see Image 1).

Image 1: Visual representation of loamy soil
Borrowed from

Image borrowed from


The main nutrients required for growing food are:

  • nitrogen
  • phosphorus, and
  • potassium.

These elements are commonly seen on fertilizers as N-P-K. In addition to this, a carbon source is also required. Things found with high nitrogen, and also contain potassium and phosphorus, are considered “greens”.
Some other nitrogen-rich materials include: fruit and veggie waste, coffee grounds, seaweed, manure, and certain plants (in high concentration) like wild rye, comfrey, and alfalfa.

Things found with high amounts of carbon are considered “browns”.
Some brown materials include: fall leaves, sawdust, straw, shredded newspaper, and dry grass clippings.

A rule-of-thumb is to have a 12:1 carbon to nitrogen ratio (C-N).

A regular schedule of mulching a fertilizing will ensure your garden is getting what it needs to maintain productivity. This includes resting your bed, crop rotation, and cover crops too.

Focus on mulching from top down (the surface contains the most oxygen and the
most biodiversity)

Some more purposes of organic matter include:

  • feeding and sheltering soil organisms, i.e. feed soil, not plant,
  • binging together mineral particles,
  • increasing soil aggregates,
  • increasing soil fungi,
  • binding particles together, creating porosity for air and water,
  • increasing resiliency to compaction and erosion,
  • cycling organic matter, releases nutrients, and
  • reducing tillage (the preparation of land for growing crops).



The No-Dig Method
Transforming lawn into garden

First Layer: comfrey leaves / manure / kitchen scraps / grass clippings
Second Layer: cardboard
Third Layer: leaves

To plant, cut a hole in the cardboard layer and plant field crops such as potatoes, squash.


Notes On Mulches
By Matt Morrison                                                                                                           

I think almost any type of deciduous leaves (these are trees that lose their leaves in the Fall) can be added to the garden and they are great; they add organic matter which enhances the soil structure; helps with nutrient availability and water-holding capacity; and they contain a multitude of microorganisms.
Leaves are full of carbon, an important source of the micronutrients, i.e., zinc, manganese and iron, which most commercial fertilizers don’t provide (i.e. they provide major nutrients, N-P-K).
Oak, pine, and beech leaves take longer to decompose and they are more acidic, while ash, popular, and cottonwood leaves are a little more alkaline. The larger leaves, like maple and chestnut, tend to clump up in the rain and mat. These leaves don’t breakdown quickly because the oxygen can’t get in and around. Waxy leaves like holly, laurel, arbutus, rhodo, pine needles take ages to breakdown so avoid using very many of those, although strawberries are acid loving plants so would benefit from needle mulch.

Ideally, it would be good to shred the leaves (this can be achieved by mowing over them) to help with the decomposing but that’s hard to get done in our garden. The trick is not to add too much (i.e., 2″ is probably enough) and not to add them directly over top your herbaceous (soft stemmed) perennials because that can cause the crowns to rot. Keep the leaves away from the stems of the plant. Leaves are the carbon side of the compost and do take up nitrogen to decompose. I tend to mix in some seaweed in and around.

Nitrogen                                                                                                                        Coffee grounds, seaweed, veggie scraps, and grass clippings add nitrogen to your soil.  You can chop up some of the comfrey in the garden and add it in with the leaves because comfrey has high nitrogen levels.

Cover Crops

A How-To Guide to Cover Cropping

Have some fall rye growing – I will cut that into the soil in early spring, as well as add some composted manure, to get the nitrogen back into the soil.

If you have a trough or rows in your garden, adding the leaves into the trough is an excellent idea…they will sit and decompose over the winter and then you can turn them into the soil in spring, and add some manure. And if you can shred them, even better. Not too thick a layer so that oxygen can get in and around…and add some nitrogen (manure, coffee grounds, comfrey, grass clippings, okara, veggie scraps) in the early spring.

P.S. I’ve read that avoiding walnut leaves is a good idea because apparently they secrete a compound that is detrimental to tomatoes. Also, I’ve read that eucalyptus, bay laurel, juniper and cypress are not good because they have acids that impede microbial life (Jeavons, How to Grow More Vegetables, p. 44).


Notes On Seaweed
By Matt Morrison

Just as trees lose leaves in fall, so do seaweeds, the result being a bountiful harvest for savvy gardeners. Seaweed adds nitrogen, phosphorous and other trace elements to gardens and composts easily, says University of Victoria professor John Paul Volpe. They effectively compost in the ground  barely needing to be treated, said Volpe, an environmental studies professor. This is a very simple way to increase the health of your soil. But seaweeds like kelp, eel grass, sea lettuce and bladder wrack need to be well-rinsed to get rid of salt, according to a local garden shop. You can lay it out on your driveway and let the rain do it or rinse it off with a hose, said Gardenworks manager Janice Rule. Rule advised chopping up seaweed and mixing it into soil to avoid its pungent odour, Using kelp in a garden has other advantages for environmentally-conscious gardeners: a chance to avoid petroleum-based commercial synthetic fertilizers. Post-Kyoto days everyone is conscious of their footprint as it pertains to oil consumption so a product that is being literally thrown up on the shore for us to use, Volpe said.

Reprinted in both the Saanich and Oak Bay News

 Manure by work study and manure lover Christina Ross

Manure: The in’s and out’s of using our sometimes smelly friend safely in the organic garden

Describes the how, when, why, what, where or using manure safely in the organic garden.


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