The Guerrilla Gardening Guidebook – Sunlight


“First Rays of Sunlight” – Stone Cairn – Frick Park – Pittsburgh, PA – Another renegade activity I take part in… Natural sculptures made of stones found on site…


This post is part of a larger body of work titled ”The Guerrilla Gardening Guidebook”. For the introduction and table of contents please click here

Urban environments can be thought of as a collection of microclimates, one of the greatest determining factors of these is the sun. Plants require sunlight to survive, so gardening often becomes a hunt for the best sunlight. Knowing a few little facts about the sun can help you determine where the best light in an area will be.

The earth spins around the sun in a counterclockwise motion. If the earth was straight up and down the sun would be 90 degrees to the earth at all times, the result of which would be no seasons. Because the earth tilts 23.5 degrees, in the winter we are tilted away from the sun, and in the summer we lean towards the sun. The sun rises in the eastern sky, and sets in the west. During the summer months, the sun passes directly overhead. During the winter months, the sun will be much lower in the sky and to the South. March 23rd and September 23rd are known as the vernal and Autumnal equinox, this is the day the vertical sun crosses the equator.

Walls that face to the south will act as heat traps, the reflected sunlight heats the ground, and in turn will heat the area at the foot of the wall. North facing walls on the other hand can experience nothing more than indirect light most of the year, this side of a building will stay frozen much longer than the south facing wall during the spring thaw. The effects of this can raise your USDA hardiness rating a zone or two on the south facing wall, and possibly lower it on the north wall. The reflection of solar energy is known as albedo and can be harnessed for use in the garden, this is a subject I have already explored in a previous post… You can find my post here- Albedo and Absorption of Solar Energy


“Sunlight Through Pineapple Sage” – Whitney Avenue – Wilkinsburg, PA – The first peaks of sunlight photographed through my pineapple sage… This salvia is photosensitive… Meaning it blooms only after we reach a certain amount of hours of sunlight… In this case around 12 hours of light and 12 of dark… AKA – Fall…

East and west facing walls are a little more complicated, even if both walls get the exact same amount of direct sunlight. The first thing you will notice through observation is that the soil at an east facing wall is always drier than the west. The wall to the east has the benefit of warming throughout the course of the entire morning, although the west wall is also warming, it is happening much slower. By the time the sun starts warming the west wall, the ambient temperature is up, and the east wall does not loose heat as fast as the west after nightfall. Because of this, you can often get away with plants typically suited for full sun on the east side of a building, and plants suited for full shade on the west.

I have published several other articles about shade gardening, for that reason I will not be writing about it now… Instead you can check them out from these two little links – Gardening in the Shade – Woodland Mimicry in the Urban Garden

Determining the type of sunlight you are working with will not take all day. Now that you understand how the sun moves across the sky relative to the current season, you will be able to map your gardens sunlight without even being on site. Just remember the sun rises in the east and sets to the west… The sun will be high in the sky in the summer… And low and to the south in the winter… Eastern sunlight is always better than west, and south facing walls create a warmer microclimate than walls facing other directions… Easy as pie…

plant petunias and question everything – chriscondello

This site… And all the photographs and information presented within are provided free of charge by the author… I am not affiliated with any product or business… Only myself… Writing this blog takes a ton of time… If you find any of this information helpful, please consider purchasing a print from my online store… It is obviously not a requirement… But it helps…

I sell prints of my photography here – Or you can contact me directly at for commissions or locally/personally produced prints… Thank you for reading…

Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.


One thought on “The Guerrilla Gardening Guidebook – Sunlight

  1. thehumansarah says:

    patience! i dont know if i could ever do it but those rock people are neat


Comments are closed.