I always tell people to focus on growing their soil, not their plants. If you optimize the soil structure, biology, and conditions, the trees and plants will grow and you will hardly need to amend or fertilize. The soil needs to be the focus for healthy and vigorous trees and landscapes. Ultimately this will not only save your trees and plants but will also save you energy, time, and money.
The most common soil problems I come across are usually a lack of organic matter and high soil compaction. In urban landscapes, we have many problems with infrastructure confinement, hardscape, drainage, foot, and vehicle traffic, and a variety of other conditions that adversely affect root health and development. Because many home landscape soils are often obsessively and repeatedly cleaned, chemically treated, disturbed, and exposed, the natural processes that would otherwise continue the decomposition of organic matter into the topsoil, for instance, an annual layer of leaf duff on a forest floor or grazing animals adding manure, is interrupted or nonexistent.
Because plant roots naturally depend on the nutrient cycles and soil biology that come from the replenishment of decaying organic matter for development, we need to address this most commonly ignored and most crucial aspect of tree and plant cultivation. Both problems of the lack of soil biology and high soil compaction can be mitigated or solved with the application of organic matter and/or mulch.
What are organic matter and mulch?
For us, organic matter is any material that comes from biological organisms, plants, or animals, that has broken down, decomposed over time, and can again be reintegrated back into the soil. The most common and useful form for our purposes is compost.
Mulch is material that can either be organic or nonorganic and is applied to the surface of the soil for reasons of aesthetics, weed suppression, water retention, erosion and compaction mitigation, and insulation from soil temperature extremes. Also, the correct organic mulch can naturally replenish and rebuild the soil through decomposition.
Many mulch products commonly used and sold are not ideal and can be counterproductive to soil and root health. Synthetic mulches like landscape fabric, black plastic, and even cardboard inhibit the exchange of oxygen and water and can also interrupt the breakdown of organic matter between the soil surface and root zone. Most people know plant roots need water and nutrients to grow but many lack the awareness that plant roots also need to breathe. That’s why it is critical for any mulch used to allow for the optimal exchange of air between the root zone and the soil
surface.
The best mulches are organic, and the best organic mulch is arborist wood chips.
Many of the organic mulches you can buy from the nursery, hardware store, or soil yard can contain a high content of bark, dyes, and other materials that resist decomposition. People often choose these products because they perceive them as the most aesthetic. One of the most common products I have seen is cedar bark mulch. Cedar bark can look good but remember that bark is the part of the tree that provides the outer protective armored layer. It is the first line of defense against attack, and decay, and its structure and composition resist water and breakdown. If our overall goal of mulching is to retain water and build the soil through decomposition, products containing mostly bark are not the best choice for our landscapes.
Arborist wood chips are the remains of trees that a tree service has processed through a woodchipper. These chips contain all the tree parts including the bark, cambium layer, sapwood, heartwood, branches, and leaves. Although they may not look as conventional as cedar bark or dyed black mulch, arborist wood chips are the best option for optimizing all the categories of mulching purposes. They suppress weeds by depriving the seeds of light and germination, they retain water by having all the tree parts of different sizes, compositions, surface textures, and levels of breakdown. A good layer of wood chips will protect the lower soil levels from compaction, and erosion and insulate them from temperature extremes. This will also improve drainage and air exchange in the root zone. Most importantly, arborist wood chips are the best mulch for building optimal soil structure and providing nutrients through the slow continual breakdown of different types of organic matter, stimulating the amount and diversity of soil organisms that are the key to soil and thus plant health.
Spread those arborist wood chips!
One of the best things about arborist wood chips is that they are free! Tree services will gladly drop a pile of them off in your driveway. Just contact a local tree service or coordinate a drop-off through chipdrop.com. I usually recommend a layer of compost and up to six inches of wood chips applied at least once a year in the spring just after the first flush of weeds.
In the mission of optimizing the health and aesthetics of the landscape, our goal is to have no exposed soil in any of the planting areas. The ground should either be covered with plants or mulch. The only place you find completely exposed soil in nature is in a desert. Spreading arborist wood chips is the cheapest, easiest, and most effective way to improve the health of your soil and landscape today.
Get some arborist wood chips for free! Many local tree services would be happy to drop off a load of wood chips in a convenient location, like a driveway or open space, for free. Contact your local arborist or tree service to schedule a drop-off or use an app service like chipdrop.com to coordinate one! If arborists can't find a place to drop their chips, they will need to pay a large fee to do so at a transfer station so it's a win-win for everyone and especially the soil!
I recommend getting a soil test to see what your soil may actually need.
Never amend or fertilize the soil until you get a soil test that says you need to do so. I recommend sending in a soil test through UMass Amherst:
Dr. Linda Chalker Scott has researched and published extensively on the use of arborist wood chips in the landscape, and I highly recommend visiting her website for more information and resources on the subject:
Schedule a tree and landscape consultation today! cyclingarborist.com
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