Deep Soil

26 / 7 / 17

Deep soil

“Deep soil zones enable planting of significant vegetation, which has the ability to grow to a mature size and provide a permeable ground surface alternative to paving or other hard surface treatments, which allows infiltration of surface water into the soil. “ (Tweed Shire Council, 2012, p. 7)

As our cities become more populated with urbanisation, resulting in high rise apartment buildings, there is also a trend for childcare centres to be offered as part of the building envelope. When a childcare centre is provided, say, on the fifth floor of such a building, what then becomes the definition of an “outdoor play and learning space”?

Deep soil is being debated as a defining element of “being outside”. Surely at least one tree should be grown in an outdoor learning area? A wispy palm in half a wine barrel is not a tree. Children need to see the spreading branches of a tree being ruffled by the wind; glistening in the rain… they need to experience a leaf spiralling down from the branches to the ground. They need to understand the “treeness” of a tree!

Deep soil: it says it all – one can feel that connection to the ground… Feeling “grounded”, feeling part of the earth, and its natural systems. This connection cannot be attained with a digging box or raised garden! Only deep soil can grow a tree; only deep soil supports a viable ecosystem. An excellent children’s book has been published this year all about soil: Exploring Soils: A Hidden World Underground by Samantha Grover and Camille Heisler. The book features an engaging child-centred storyline with captivating illustrations, and it aligns with Australian curriculum and Soil Science Australia’s ‘Soils in Schools’ initiative!

Deep soil is heavy, and in some high-rise buildings, this needs to be factored in so that the slabs and columns can take the load of soil plus a tree. But generally it is best practice to plan the childcare centre to be on natural soil profiles at ground level. Check your local council’s requirements for deep soil landscaping for childcare centres; it will likely consist of a percentage of the outdoor space.

Tweed Shire Council. (2012).  Review of Tweed Development Control Plan, Discussion Paper 3: Landscaping, deep soil planting zones and outdoor areas. Tweed Shire Council