Soil Day with John Slack

John Slack lives in Erin Ont. He has been a friend of the community garden for a few years. He is well know in organic farming circles. It is with pleasure that we have invited him to come to our garden to speak with us about the soil that we grow our food in.

For the presentation there was: John Slack, and his brother Peter Slack, Klass Baan and his wife, and Dave Dittmar.

Guests and visitors were: Mike Neven, from FoodShare, Sunny Lam and David Wild from Food Cycles, Deveri Gifford and gardener from The Christie Pits Community Garden, Audrey Yates from the Garden Party hosted by Lutheran Redeemer, Miro Zawistowski, Brenda Heyer and her son Miro.

From our community garden there were: Andrea and her husband McCloud, Anna and her son, Gaye, Alison, Yves, Kevin, Shirley, Tony, Dahlia, Edward, Edmond, May, Nao Ito – Honorary Gardener and everyone's favourite volunteer, and me Susan.

To begin Soil Day, I introduced John to the group that had gathered. We had a round of introductions for most of the peoples names and where they came from, and then John started to speak. In his introduction he spoke of his mining heritage from his father, and how, through a chain of events he got involved in agriculture. The chain of events continued to where the mining and the farming combined to get to the point of the agro-mineral knowledge and expertise. He explained his interest in the Spanish River Carbonatite. He described it as an incredible soil amendment that adds a multitude of macro-, micro-, and trace minerals back into soils. The Spanish River Carbonatite(src) works hand in hand with compost and When it is added to the compost, it provides the microbes in the compost with a wide array of the nutrients they need to thrive.

He went on to talk about compost, and that the best part of adding any compost to your beds will be the increase in microbial life that it will bring. Once you get the life cycling back into your soil, their productivity will be unmatched.

---

Next, John brought out his Dutch Auger to demonstrate how he tests the soil. Unlike traditional soil tests which only look at the soil within the first 6", John uses a dutch auger and examines the soils up to a depth of approximately 3'. By examining the soils to such a large depth, John is able to see the various soil strata (i.e. soil layers). These strata are very important in determining the nutrient levels of the soils, the nutrient holding-capacity of the soils, as well as the microbial life within the soils. You see, the formation of layers within the soil is all a function of the microbial life within that soil. No microbes = no strata differentiation.

We used the middle of the park as a likely place to do the demonstration. the cutting blades of the auger are about 6" long and are at the end of a 4' long tool. His first cut is just as deep as the blades, and as he rotates the tool he goes down into the soil. He then carefully brings it up and places the soil down in front of him. He continues this procedure laying the soil down in a consecutive manor, until he has reached about 3' deep.

Ideally, John likes to see several distinct soil strata including (from upper most layer to bottom) the humus, the topsoil (A Horizon), the Subsoil/Leach Layer (B horizon), Parent Material (C and D horizons). More often than not, the soils in our gardens and in urban environments lack adequate humus and top soil. These two layers tend to be very biologically active and mineral/nutrient rich. John also tests the soils for calcium levels using a weak hydrochloric acid solution.

John hammered home the point that biologically active calcium is vital to all healthy soil and plant systems. Without adequate calcium levels, plants just could never obtain optimal health. Typically, John will spray his acid solution on the B and C horizons (check the Diagram) and watch for a reaction. If there is a lot of free calcium in these soil layers, the acid will react violently and produce a lot of fizzing action. If these soils lack adequate calcium, there will be almost no reaction at all. --- Please click here for the Pictures and diagram for a better visualization of the desirable soil strata, and the soil that John found in the park.

---

After a while, John opened the conversation up, and people started to ask questions. We talked about bio-intensive gardening, how the mulch works for you, and not digging up your garden every year. The micro organisms have their little society, and they get killed, and have to rebuild when you dig up your garden. especially if you use a rotor-tiller. Then the question came up, should you double dig each year? The answer from John was -no-, if you double dig your garden bed, properly, you don't need to do it again. John, lamented that he didn't have a way to demonstrate the way he does it..... I spoke up on be half of Gaye, (she had mentioned her desire for leaning how to do this for her garden) I mentioned her carrots with the flat bottoms! So at that point we all walked over to Gaye's garden plot, and offered John a selection of shovels to choose from.

---

Double Digging – the real technique

The purpose of double digging in your garden is to loosen the deeper soil, so that it is easier for the roots of your garden plants to go deeper into the ground and to allow the micro-organizems to circulate, and the important elements from your compost to circulate as well. The first step is to lift the topsoil away from the secondary level of soil. Working one row at a time, start to remove the top layer of soil away with a shovel. To conserve your energy we suggest that the first row is placed into a wheelbarrow. About 15 – 20cm below the surface of the soil, you will notice that the soil looks different, and has a different colour and texture, this is the "subsoil" mentioned earlier. This is the part that gets the double digging, well not in the traditional way. We don't want to up-set the micro-organizims too much, so switch to a pitch fork and stick in to this layer and move it back and forth to loosen it. Every 10cms insert the pitch fork and loosen the area up.

For the next row, you can move the top layer of dirt into the trench that you have created in to the previous row. As you work across the garden in this manor, you will notice that the soil has more loft, with out having added anything yet, the soil level in your garden is raised. When you arrive at the last row, move the soil into the previous trench, and loosen the soil layer below, as in the rest of your garden, and then, get that wheelbarrow full of the first row of dirt, and bring it here to the last row trench, and fill it in.

At this point some stayed to watch as John and Dave finished that side of Gayes' garden. Others broke off into small groups to discuss the things they had learned, or to walk around the garden.

We were happy with the turn out for this presentation, especially considering that it was a Civic Holiday.

Many of our guests came on bicycles.