Micro-Climates Large and Small

An amazing ‘teachable moment’ occurred recently regarding the concept of micro-climates. The “Black Boy” peach stones have been in sand – black sand from the west coast of New Zealand – for the winter. This is our germination strategy.

About four weeks ago, due to changing seasonal sun angles, morning sun reached under a shed roof and struck one small part of the beds. The resulting warmth caused early germination of five seedlings in one little spot. Only now are stones germinating in the rest of the beds.

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That teachable moment gives way to larger discussions on micro-climates and how they can be embraced, designed and improved. While our market gardens are out in the open and often take heavy winds, we have a smaller ‘kitchen garden’ protected from the prevailing winds that also benefits from the ‘sun trap’ effect created by the home and carport.

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We shifted the herb garden to this north-facing location in the car park. Most herbs love hot and dry conditions, as does the dog.

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Similarly, these grapes grow in a north-facing sun trap that is also protected from the prevailing winds. Additionally, most of the leaves are kept dry by the shed roof, which reduces the chance of moulds and fungus growing on them.

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Plants in the nursery receive morning sun but are protected from midday and afternoon sun in the summer.

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The potting bench also receives morning sun but nothing else. This is good for transplants and hardening off purchased seedlings grown in hot houses.

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With heavy soils we have struggled with where to plant citrus. The solution was to build up a “hugel-mound” to improve drainage and increase soil carbon, and to site it in a spot protected from the prevailing winds by existing lacebark and recently planted tagasaste.

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While micro-climates often seek to achieve protection from the wind, there are instances when the opposite is desired. Evapotranspiration beds seek to draw moisture out for the soil using plants and a windy location. This from Wikipedia:

Evapotranspiration (ET) is the sum of evaporation and plant transpiration from the Earth’s land and ocean surface to the atmosphere. Evaporation accounts for the movement of water to the air from sources such as the soil, canopy interception, and waterbodies. Transpiration accounts for the movement of water within a plant and the subsequent loss of water as vapor through stomata in its leaves. Evapotranspiration is an important part of the water cycle. An element (such as a tree) that contributes to evapotranspiration can be called an evapotranspirator.[1] 

Below is a sketch of a mounded ETS bed for grey water treatment using biomass willows and carex grasses. The idea is that the willows grow rapidly in the presence of the  nutrients in the grey water but transpire excess moisture to the atmosphere. In winter when the willows are dormant the grasses take over the transpiration task.

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By understanding micro-climates we can use them to our advantage. These are examples of using the permaculture principles: Observe & Interact, and Design from Patterns to Details.

Peace, Estwing

Estwing