Updated: Mar 31, 2021
"Plant people" know that aeration of a soil produces happier plants and soils which then require little of our help in producing a crop or newly planted tree living for hundreds of years. But over the last century we have focused on improving yields by adding nutrients and ensuring water availability. These have become the primary necessities and skills which humans use to grow plants. Aeration is an acknowledged necessity but not given the attention. Its accidentally provided by giving the soil we use the ability to drain well by adding aggregates and organic matter. In fact, in many commercial nurseries and glasshouse operations, soil is barely used at all! Instead organic matter is the medium which enables ‘maximized’ water retention and nutrients supplied by slow release fertilizers. Hydroponics is the ultimate example of a completely managed ‘soil’ but it too has ample aeration integrated into the continually circulating water solution.
Air is not a commodity as nutrients and water are. Air is freely available and not something humans buy or turn the tap on for. It has become an ‘accidental necessity’ – an assumption – something we have to be aware of but have not put at the top of our understanding of what the plant needs to thrive (and to simply survive). Plants can adapt to deserts, mountain tops and even be Bonsaied! - go with long periods of time without water and few available nutrients but they must always have aeration so that oxygen is always available and gases such as CO2 can escape the soil mass were its buildup (and other gases) which, if allowed to build up, damage the living cells of the root, the mycorrhizal systems and living soil creatures, earth worms for example.
It is this buildup of gases under the hard surfaces of City structures which is one of the biggest killer of trees – that, and the compaction levels of the soils into which the tree is ‘supposed’ to grow roots. If we "plant people" don’t make aeration our first priority then how can those who want to grow plants but freely acknowledge that they do not have the experience, then be able to recognize that without air, plants (and soils) die. They literally don’t ‘see’ the problem. Pocket Woodlands® are planted on raised soil areas for exactly this reason – so that the soil is continually aerated and free draining, thus enabling rapid and deep root growth along with enabling a healthy mycorrhizal/earth worm population to establish. Then the trees/plants and soils become almost maintenance free as nature’s systems look after themselves and adapt to the circumstance and seasons. For the future, our primary skill is to ensure that aeration is always present for the soils we provide so that we can enjoy, for the hundreds of years that the trees that want to be able to live in our varied cityscapes.