Sunlight is a dynamic and critical element to your garden. The sun constantly moves throughout the day, as well as from season to season coupled with human-influenced elements such as buildings, walls, and other plantings and you’ve got a surprising number of factors that all need to be considered when accurately determining the amount of sunlight your garden gets at different times.
At first, determining how much sun your garden gets seems pretty simple and straightforward – you take a look and see if there’s sunlight hitting the ground. Done. Right? Well, not so fast.
Seeing sun and believing that a space is “sunny” is perhaps the biggest mistake novice gardeners make. Many coveted plants grown for their abundant floral displays, colorful foliage, and even most of those yummy edible plants require as much as six hours of sun a day, and since there are several factors that influence how much sun a garden gets, it’s important to assess the time and duration, intensity and filtration that come along with the availability of sunlight. Especially because the second biggest mistake is seeing shade and assuming that a particular spot is shady. This can be a struggle for plants that really want to live in three or fewer hours of sun on their backs and find themselves baking to death.
Consider this: In the summer, the sun is higher, generating shorter shadows. In the winter the sun is lower on the horizon, creating longer shadows. How much sunlight falls on your garden varies widely throughout the year.
Create a simple map of your shade using graph paper and noting the shadows of some of the biggest shade-makers on your property (trees & buildings), you will get a clearer picture of the true level of sun exposure in your garden. You need to do it at least twice in the year – once in the summer and once in the spring or autumn. Spring and autumn sun and shade patterns can be quite different even though sun angles are similar. This is because of the amount of foliage present, so if you really want to understand your exposure, map in all four seasons at the equinox and solstice. You can even take it one step further by assessing your light patterns every couple of hours during various days throughout the year to get an even more precise understanding of the evolving balance of sun and shade from he different seasons.
You will be able to choose your plants with confidence once you have a clear picture of your garden’s sun and shade characteristics. Always bare in mind that a plant’s light needs are more dynamic than static, meaning, you can get various levels of performance from a plant depending on the balance between the characteristics it loves and those the area provides. For example, if you plant a sun-loving plant in an area with dappled or intermittent light over parts of the day, you won’t necessarily kill it, instead, you’ll experience fewer flowers, less color and possibly a shorter life span.
Always remember that deciduous trees offer seasonal shade and that leaf-out and die-off action will significantly change the amount of sun your garden receives. Spring sunlight under leafless boughs provides the perfect stage for an early-season flower show that will quietly fade as leaves emerge and shade deepens. Seasonal light patterns should be taken into consideration when you choose and situate plants for your garden because it allows you to plant different varieties that can take advantage of the light in a particular location as it changes.
It is also very important to note that your sun and shade patterns today will be quite different in the next 5 to 15 years from now. Neighboring plants get wider, denser and taller as they mature, creating more shade over time. This is all part of the normal ecological succession patterns. Integrating this knowledge into your planning can be very useful as you design your garden.
