Sun & Orientation

The rotation and position of the earth in relation to the sun affects the light coming through your windows.  For our purposes, orientation is the positioning of your home and windows in relation to the points of a compass and the direction of the Sun.

Understanding the orientation of your home will help you work out the way light enters your home and where your plant/s will thrive.   

To determine the orientation of your home and windows, use a map, street directory or even a compass set to show true north on your smartphone.  

You can move your plants about your home as seasons change and the sun moves or you can adjust watering and other care needs to suit your plant's limited conditions for a period of time.

To understand the movement of the Sun, we need to look at a few terms and principles.  

Earth rotates along a fixed axis, an imaginary line through the centre of the Earth (north to south pole) once every 24 hours.  While rotating, the Earth also orbits around the Sun once every year.  The elliptical path that the Sun appears to travel around Earth is known as the Sun's path. 

In the southern hemisphere, the Sun's path across the sky is predominantly to the north.  In Northern Australia including Darwin, the Sun's path moves to the south in the wet season instead of to the north.  This is because we are north of the Tropic of Capricorn, the name given to the southern most arc of the Sun's path (summer Solstice).

The Solstice, latin for 'sun-stopping', is the point where the Sun's path appears to stop moving (north or south) and then returns in the opposite direction.  

The summer Solstice in late December is when the Sun appears further south in the sky each day until it's over the Tropic of Capricorn.  It is the day that has the most daylight (approx. 12.5 hours). 

The winter Solstice is late June, when the Sun moves north in the sky until it's over the Tropic of Cancer.  It is the day of the year that has the least daylight (approx. 11.5 hours).

The Equinox, latin for 'equal night', is when the Sun is directly over the equator as it moves between the two Solstices.  The autumn Equinox occurs in late March and the spring Equinox occurs in late September.  Days and nights are the same length at this point in the sun's path.  

Eaves, window shades and coverings help keep light and heat (radiance) out of your home.  For windows receiving harsh direct sun, this may be a good option for your plants too.

Eaves have little affect for direct sun when it is low in the sky; think morning, afternoon and north facing windows in the dry season.  Consider temporary shade options or window coverings to block out harsh rays but allow bright indirect light at other times.  

Eaves over south facing windows provide excellent shade for the high wet season sun.  

The more reflective your window shade or covering is, the more radiance is bounced away.  A completely reflective shade lets no light or heat through at all.  

Greenhouses often block out only 30% of the Sun's rays but can be up to as much as 50-70% for seed raising and propagation purposes.

In Darwin, cool breezes come predominantly from the north-west however it's helpful to consider and maximise the cross-flow of breezes as much as possible.  Planting outside windows to filter light while still letting air flow through is a good option.

Vegetation in your yard and that of your neighbours can affect the light entering your home, particularly when the Sun is low in the sky.  The size and shape of your neighbours’ homes or any adjacent buildings will also likely obscure the Sun at different times throughout the day.  Large trees and shrubs, fencing and screening provide some respite from the harshness of direct Sun.  

For north facing windows, hard pruning of vegetation at the beginning of the wet season will allow lots of light in, then light aesthetic pruning at the beginning of dry season will minimise the amount of low northern Sun filtering through.

Plants grow in almost all climates, so there is a suitable plant for most places in your home.  Having said that plants require light for the process of photosynthesis so it really is essential.

When the Sun is lower in the sky (early morning, late afternoon and also dry season when Sun is to the north), direct Sun will extend further into your home. Plants can therefore be placed a metre or more away from a window and still receive some direct light.  

Radiance is often amplified by windows and so care must be taken, particularly for west facing windows (wet season) and north facing windows (dry season) to ensure plants are not being burned by the afternoon Sun.  

When the Sun is high in the sky (wet season when Sun is to the south), plants need to be closer to windows to get as much bright light as possible.

Use our Sun Trackers (available on our subscriber only Downloads page) to help work out the Sun's movement and the best place for your plant in your home or space.  If you are not a subscriber of The Plant Paper already, consider subscribing today!