What is Structural Soil and Why is it Good for Trees

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What is Structural Soil Why is it good for Trees?

Why is structural soil effective?

Structural soil is a type of soil mixed with a specific type of gap-upgraded rock (typically 75mm clear). This is a very important part of the specification; the reason structural soil works well is that the gaps created by the rock are then filled with soil, enabling penetration by tree roots. This penetration allows the tree access to a larger space underground, and has the double function of preventing the tree roots from lifting up the hard surface, i.e. the sidewalk that is on top.

How does the structural soil get tested?

The testing of structural soil is essentially a three-part process. The soil must be tested separately. The rock must be tested and sourced with a specific sieve size attached to it to determine that it is in fact a clear rock and not a minus rock. With a minus rock all of which would be filled and therefore the soil would be effective.

There is also a stabilizing compound that is used with structural support to help the soil adhere to the rock. The specifications for this material would come directly from the stabilizer supplier; there are more than one of these.

Who can make structural soil?

Like any engineered soil, structured soil is a technical process which is best done by people who understand all the specific components and have all the components readily available with testing and prior knowledge. Making good structural soil to specification is an extremely important endeavour. Structural swell that is not up to specification is a very difficult situation to remediate once it’s already in the ground.

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Dealing with the Chafer Beetle – Nematode Protocol Update

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Dealing with the Chafer Beetle – Nematode Protocol Update

Two options for addressing chafer beetle infestations

Are you or your clients having problems with the European Chafer beetle destroying lawn?  We suggest the protocols described below. Please keep in mind that the insecticide must be administered by a professional with a pesticide applicator’s certificate. The rest could be done by a homeowner, but it is a procedure that is far more likely to be done by a landscaper.

The first option is to do an Imidacloprid drench. After the drench, wait a few weeks, then remove the turf and as much soil as is reasonable—a minimum depth of 2 inches. Next, add soil to required depth; the soil can either be Terraseeded, hand seeded, or lay sod. Make sure to do this in late July/early August before applying the nematodes.

By removing the turf and some soil, you’re taking out most of the grubs, even the ones killed by the Imidacloprid. The large grubs are more difficult for the nematodes to kill. Applying nematodes after egg-hatch (in mid-late July) will target the small grubs, which is more effective. It should be emphasized that nematodes should be applied annually if the Chafer Beetle continue to be a problem in their area.

There is the issue that not all jurisdictions allow the application of this insecticide. Therefore, each customer must find out what is acceptable within their jobsite and municipality.

If insecticide use is not permitted in the area, there is a second option. First, apply the nematodes at recommended rates to the soil in April through June, and then again in September through early November; the nematodes should be applied in areas of known infestation where specific lawns show signs of chafer infestation. Remember that the lawns must remain damp for at least two weeks after nematode applications.

For both options, it is very important to follow healthy lawn practices as well established lawns are more resistant to chafer damage. These practices include aeration and topdressing, watering well at appropriate intervals, consistent fertilization, and cutting to a 2-inch height (not too short).

 

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Remediation

In order to resist the chafer beetle when projects are newly installed, consider the following recommendations. First, if permissible, drench the soil with Imidaclorprid. Then, excavate and dispose of native topsoil to a reasonable depth of 2-6 inches. Replace the excavated material with compost-based soil; the type of soil should be based on specific requirements, i.e. turf.  If applicable for the application, the use of grass species such as tall fescues and alternatives such as Microclover will help resist the beetle.   Overseed the remediated areas at 3-4 times the suggested rates; in theory, this makes it difficult for the chafer to get to the surface. It will also make it harder for the chafer predators (birds, raccoons, etc.) to do damage. Lastly, encourage the use of any product or method that will increase turf establishment as well-rooted turf will stand a better chance.

Overall, it is important to remember that the European chafer beetle is an ongoing problem that is unlikely to be solved easily. There is no silver bullet. Providing quality products and installation combined with a willingness to maintain the remediated areas will improve the customers chance of a successful project.

Check out our full infographic on “How to Deal with the Chafer Beetle”. Enjoy and please share!

 

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Here are some other resources we have found online that may be of help:

 

https://www.burncolandscape.com/chafer-beetles-lower-mainland/

 

http://www.cuttingedgevancouver.com/services/chafer-beetle-control/

 

http://www.landscapingvancouver.ca/chafer_beetle_vancouver.html

 

http://www.artknapps.ca/preventions-and-treatments-of-chafer-beetle/

 

http://www.coquitlam.ca/city-services/environment/european-chafer-beetle.aspx

 

www.coquitlam.ca/docs/default-source/city-services-documents/coquitlam—chafer-beetle-2015.pdf?sfvrsn=2

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BC – A River Delta: Understanding Soil. Ask Tom Series

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The River Delta Soil

There’s a perception in the lower mainland of British Columbia that because we live in a river delta, all of our soil is ideal for growing. This puts to question the need to purchase manufactured soil.  

We decided to “Ask Tom” his opinion on the matter.

Interviewer:

Tom, we live in a river delta so why do people need to purchase engineered soil? Shouldn’t our native soil be ideal for growing?

Tom:

Yes, we do live in a river delta and much of our soil is good for growing. However, in the land development process, the top layer of organic soil is usually removed.  Some of this soil is actually really good. The problem is you can’t guarantee it’s composition. To ensure that your soil is the right composition for growing, it is best to purchase engineered soil.  

Soil structure an important aspect of a grow medium.  There is a difference between good soil and the right soil structure for a grow medium.

Interviewer:

What is right soil structure?

Tom:

Good Question.  Let me tell you about our engineered soil and why, in my professional opinion, it provides the best soil structure for your grow medium.  

First, We ensure that our engineered soil has the right amount of Sand, Silt and Clay.  We also test that the ideal amount of water and air are able to move throughout the soil.  

The sand used in our soil composition is a medium-fraction river sand. Since we have such a large river running through the southern portion of our province we have amazing access to high quality of sand. The Canadian Government of Fisheries does an amazing job of conserving the river while still allowing proper access to the sand.

So there are three main components, sand, silt and clay, to an engineered soil.  At Denbow, we regularly test our soil to make sure it is in the right amount of these parts.  Our soils adhere to strict laboratory-tested guidelines and meet BC Landscape Standards. When you just mix the excavated dirt on sight, you are unable to achieve this same standard.

When you have the right structure then the right amount of air and water are able to move naturally through the soil. Air is just as important as water as it allows the right drainage for plant growth. Residents of British Columbia know we get a significant amount of rainfall. This amount of water requires our soil structure in BC to have a specific amount of sand to allow the water to drain.

To conclude, there you have it. Although the mighty Fraser Runs runs through B.C.’s entire lower mainland, we still need engineered soil so we can be successful with our landscaping.

In our next post we’ll be discussing the importance of pH balance in addition to soil structure.  

Stay tuned for more Ask Tom Articles.

Single Most Important Aspect Of Soil – Ask Tom series

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An interview with Tom on soil

We decided to ask Tom the question, “What the single most important aspect of soil?”

We were surprised by his response.

Denbow: Ok Tom, what is the single most important aspect of soil?

Tom: Ah that’s a simple question!

Denbow: Really? Tell us more.

Tom:  Of course. Now my first response was a little tongue-in-cheek. You see, there isn’t a single most important aspect of soil.  Soil is so much more dynamic than most people understand.  As I will hopefully help illuminate in this series, soil has multiple components, which can be engineered to best support what needs to grow.  These components are sand, silt, and clay, together with organic matter.  The proportions may vary, as does the PH level.  So, in fact, your question is not simple at all. A better question might be “What is the best soil composition to support what needs to grow?”

The soil is the grow medium for what needs to grow. When sourcing soil for your project, it is important to ask the right questions. In what geographic region is the soil being used? What kinds of natural environments surround the soil? What are you planting in the soil? What is the slope of the land? There are literally hundreds of questions you could ask when considering what type of soil to use on your specific project.

I could also argue that the single most important aspect of soil is having standardized soil regulations that govern soil usage.

It’s ironic that when constructing a building there are stringent rules regarding the building code, yet when it comes external landscape components of the building, there are mixed standards and styles. However, when you consider the impact of the landscape and the potential the external part of the building has on the environment, as well as any surrounding water sources, you start to see that the exterior of a building is just as important the interior.

Soil manufacturers are not equal and soils are not equal. Many different components like yard waste, compost, and, in some situations even bio-waste, can potentially contain metallic elements in the soil. This is why we need to educate the public as well as lobby for more consistent and informative guidelines for the uses of soil.

So, in constructing a building you have some clear guidelines. Attempting to create similar standards for soil has been challenging to say the least. Over the last 20 years it’s been difficult because we haven’t passed along the right information.

I can explain this way, Tom says. Soil in British Columbia and the regulations of soils in British Columbia has been like a telephone game (you know, the game you played as a kid). One person starts the conversation, whispering in the next person’s ear. “Soil needs to have these three components,” they say. The next person passes it on: “There are three things we should discuss when it comes to soil”. The next person says, “There are three important ways to install soil”. This continues until the last person says, “Soil is great for growing.” Yes, this is true but it has very little—if any—of the information that is actually useful for soil regulations.

Conversations managed this way can get lost in translation. And that’s what’s happening with BC soil. We have several people trying to establish rules regarding the soil views in different cities and municipalities around the lower mainland of BC. Although these rules are somewhat informative, they also need to be consistent and useful, and therefore easily followed.

So, to sum it all up (and sorry for the tangent at the end!), there is no single aspect of soil that is most important. Soil is a dynamic grow medium that needs to be properly engineered to meet the requirements of each specific project. From there we need to have a governing body helping define and classify the different soils we use so the project manager, landscape architect or informed home owner can make the right soil decision.

Soil Series – Who is this Tom?

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Soil Series – Who is this Tom? segment #2023

“Dirt is the stuff underneath your fingernails, whereas soil is an engineered composition of organic matter (sand, clay and organic matter) designed specifically for your project’s grow media and geographic location.”

– Tom McConkey

So who is this Tom McConkey?

Before we start talking about “soil”, we want to introduce our specialist.  Denbow is pleased to be offering this series of interviews with one of our valued partners,  Tom McConkey.  Tom is highly skilled in landscape and our local soil and has been in the field for over two decades.  Some of his specialty areas include Green Roofs, Urban Agriculture, Bio-Swales, Storm Water Management, Sustainable Turf Grass Practices.

Tom attended Carelton University and earned a degree to become an English teacher but as fate would have it, Tom decided to take a position at a local landscape company instead.

Early on there he got involved in the company’s compost practices. Tom became very interested in not only selling the compost, but understanding the composting process.

At the time, composting  was a new aspect of the landscape industry so Tom was given the freedom to get to really “dig in,” so to speak.  

During his early years, Tom was able cultivate his knowledge and skills while being mentored by Dr. Bill Herman of Pacific Soil Analysis.  Dr. Herman is a soil specialist who instructed Tom in both the composting process and more importantly, the beneficial use of organic matter as it pertains to the British Columbia Lower Mainland network.  

Denbow hopes this interview series with expert, Tom McConkey serves Landscape architects, city managers and landscapers as well as the average joe gardener in understanding the complexity of engineered soil and how it can assist their projects.  

A New Soil Series Called “Ask Tom”

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“Ask Tom”

A new series by Denbow

At Denbow, we know how important soil is.  Some people might suggest that soil is just dirt but we’ve learned that soil is incredibly complex while the success of any environmental infrastructure depends heavily upon it. Soil is the most important variable of any growing medium, whether farm, garden or landscape. In our new series, “Ask Tom,  we are going to take a careful look at soil. Iron_rich_soil_in_hand

“Ask Tom” will be an interview series with Tom McConkey, a local soil and landscape specialist who has over 25 years of landscape and soil analysis under the mentorship of Dr. Bill Herman. Throughout the series, Tom will share his knowledge and experience about soil and help break down the different aspects of soil and the importance for both professionals and laymen.

We’ll ask Tom what he believes is the single most important aspect of soil.  With Tom’s help we’ll look at the quality of soil here in the lower mainland of BC. We live in a river delta, so should our soil be good everywhere? (Here’s a hint – it’s not and we’ll let you know why.)  

dirt-ball-in-handTom says, “Dirt is the stuff underneath your fingernails, whereas soil is an engineered composition of organic matter (sand, clay and organic matter) designed specifically for your project’s grow medium and geographic location.” As we dive into the different topics, please feel free to ask your questions in the comments or via email/web form. We would love to interact with you once we get things rolling. We want this series to be helpful to those in our geographic region.

Thanks for checking in!  We are looking forward to having conversations with Tom and understanding in more depth value of soil as it relates to sustainable development and the environment through urban development. We hope to cover a lot of ground…  

 

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