Many people who develop an interest in gardening start to understand the basic needs of the plants they’re growing, including the type of soil, amount of water, and fertilizer needed. However, many new gardeners also need to understand their plants’ sun requirements.
In gardening, partial sun means that plants get direct exposure to sunlight between four to six hours a day, while full sun means that plants get more than six hours of direct sun exposure per day.
It is necessary to know the amount of sunlight and the duration of exposure certain plants require for optimum health and growth. This article will discuss the different degrees of sun exposure, the different types of shade, and how they affect plant growth.
As mentioned above, the key difference between partial sun and full sun is the duration of direct sun exposure. Note that not all sun-loving plants can endure the intense heat of the mid-day to late afternoon sun.
Plants need exposure to sunlight as a requirement for growth. Imagine a meadow full of daffodils and how much sunlight it receives during the summer. Daffodils need full sun exposure and don’t mind the intense summer heat.
Full sun means six to eight hours of exposure to sunshine without shade. Ideally, plants that require full sun must be exposed to the sun when it is brightest between 9 AM and 4 PM.
Most sun-loving plants like ornamental grasses prefer full sun exposure for optimum growth. However, an interesting thing about these plants is that they can survive even in light shade—although they will not be as tall and vibrant compared to when they are exposed to direct sunlight.
Contrary to what some people believe, plants demanding a lot of sunlight may still survive even in icy winter as they hibernate and eventually become active again in spring when sunlight becomes intense again.
Some landscape artists and gardeners design plant arrangements to strategically shield plants from sunlight at certain times of the day. This relief from the sun is necessary for these plants to grow or bloom, because too much sunlight can be counterproductive as the leaves may burn and dry out.
Plants requiring partial sun must get direct sun exposure for only four to six hours a day. Some sun-loving plants need respite from the sun’s intense heat and can tolerate only four to six hours of full sun between 9 AM and 4 PM.
Some things to consider for plant arrangement include the direction of the garden in relation to the sunrise and sunset, the climate in the area, and other structures present around the garden, such as houses, trees, or buildings.
The early morning sun is good for many sun-loving plants but does not pack enough intensity for chemical reactions to start. There must be a steady stream of sunlight for light-dependent reactions to occur in the leaves of plants.
That’s why it is also essential to consider the direction of the garden and the climate in the area because they could affect how well plants can grow in certain seasons.
Trees that normally provide shade to plants may shed their leaves in the fall and have none left until spring, so gardeners must also consider this in terms of plant arrangement.
In addition, plants that rest against a wall of a house or a building may receive varying amounts of light. For example, plants in front of an east-facing wall can receive early morning to mid-day sun but not the afternoon sun as the wall will cast its shadow upon the plants.
The popular gardening terms “partial sun” and “partial shade” are not completely the same, although some people mistakenly use the two terms interchangeably.
Partial sun means that plants need direct exposure to the sun for four to six hours between 9 AM and 4 PM. Plants needing partial sun need bright and intense sunlight around midday but will benefit from shadows cast by trees in the late afternoon.
Partial shade means plants benefit most from two to four hours of sun exposure per day, but preferably from the morning sun—between 7 and 11 AM. After which, plants that require partial shade must receive shade from natural or artificial structures to shield them from the intense afternoon sun.
Sunlight is an essential requirement for light-dependent photosynthetic reactions to occur in plants, but plants have different requirements when it comes to the amount of sunlight vital for their growth.
Five common types of sunlight are defined in gardening: full sun, partial sun, partial shade, dappled shade, and full shade. Some plants are flexible and may grow in a wide range of different sun conditions.
However, even flexible or versatile plants still have an environmental condition where they can grow best. To understand how it works, you may refer to the description of the different sun and shade requirements below:
Plants that require full sun need more than six hours of direct sunlight per day. As such, they must be placed in open areas that will allow them to receive as much sun as possible.
A south-facing garden is ideal for sun-loving plants because the area receives the most amount of sunlight from sunrise to sunset, especially in countries in the northern hemisphere.
If you are growing indoor plants that need full sun, consider placing them near a south-facing window.
Keep in mind that sun-loving plants require quite a bit of water. If the soil does not get enough moisture due to intense heat, these plants will do better in partial sun.
Plants that require partial sun grow best when they receive only four to six hours of direct sunlight. Generally, plants that require partial sun need six hours of direct sunlight in the winter and four hours in the summer. Ideally, five hours in spring and fall is enough.
However, it may not be that simple as some plants prefer the morning sun to the afternoon sun. An experienced gardener at your local store may provide some helpful tips on where to place your plant.
If you want an indoor plant, you must be up for a routine of taking your plant out under direct sunlight at certain times of the day. If you have a garden, that may prove less of a hassle as you can place your plant against the fence or next to a tree that would shield it from the sun.
Geraniums do well in partial sun next to a fence since it can protect them from strong winds. Planting them in pots also makes it easier to move them to other parts of the garden in different seasons.
When you buy a plant that says partial shade on the label, it means that it needs only two to four hours of sunlight per day. However, this can get tricky since some plants thrive well in the gentle early morning sun, others in the intense late afternoon sun.
Some indoor plants sometimes lean towards the light source. It means that the area where it is does not have enough sunlight. The direction where the leaves grow more or lean towards is like the plant’s gesture that it must be moved towards a place where it can get more sunlight.
If you are thinking of having an indoor plant, try placing it next to an east-facing window for one to two weeks. If you notice that it’s not looking as vibrant as you hope, you may try to move it next to a west-facing window and observe.
It may seem troublesome, but as discussed, there are many factors to consider when deciding where to place your plants or what kind of plants to get. The climate in your area and the different seasons can influence how well your plants can grow.
If you are not sure about which plants will grow well in your partially shaded garden or room, you may try a lovely pot of periwinkle (Vinca minor). It is a shade-loving plant but wouldn’t mind a little bit of sun for two to four hours a day.
Some plants need one to two hours of direct sun exposure and may thrive with only dappled sun the rest of the day. Plants underneath the shade of a tree get sunlight from the gaps between the leaves during midday (10 AM to 3 PM) as the sun goes up.
The plants’ direction in relation to the tree and the amount of foliage on the tree every season can affect the growth of the plants.
Bluebells grow well in dappled sun because they can’t tolerate prolonged exposure to direct sunlight. The space underneath the tree also ensures that the soil has more moisture compared to open areas.
However, plants in this situation need to compete with the tree’s roots for moisture from the soil. Gardeners need to consider this when selecting plants to put under the shade of a tree.
People who are new to gardening often mistake full shade as having no sun exposure at all. Full shade does not mean the absence of sunlight. It simply means that plants under this condition get less than an hour of sunlight per day.
Plants usually get full shade underneath canopies of trees and get only a bit of sunlight from the gaps between the leaves all day. Some plants like ferns thrive well under full shade.
Kitchen and living room plants generally require full shade. A good rule of thumb is to place them next to the window to get enough sunlight they need.
If the window faces east, the plant can receive light from the early morning sun. If it faces west, the plant can get late afternoon sunlight. These conditions are suitable for plants requiring full shade.
A south-facing window is not good for plants that require full shade because sunlight can pierce through the window all day. A north-facing window is good because the plant may not get much direct sunlight all day, but it is enough for its light requirement.
Gardeners have a lot of plants to choose from when planning how they want their gardens to look. Some may enjoy a colorful garden with plenty of flowers or plants with colored leaves for a vibrant view. Others may wish for a lush green for a relaxing sight.
On the other hand, some apartment or condo dwellers who don’t have enough garden space may still want some greens at home. When selecting a plant, it is best to consider the location of the unit and the amount of sunlight it receives in a day.
No matter how you want your garden or room to look, you must always pay attention to your plants’ sun requirements. Here is a table showing the different sun requirements and some corresponding garden and potted plants:
|Full Sun||Daffodils, Yarrow, Lavender, Aloe Vera, Croton, Cactus, Daisies, Hibiscus, Platycodon, Irises|
|Partial Sun||Heliopsis, Geraniums, Amsonia|
|Partial Shade||Periwinkles, Primrose, Hosta, Fingerleaf Rodgersia|
|Dappled Sun||Tuberous Begonias, Bluebells, Daphnes|
|Full Shade||Autumn Ferns, Lenten Rose|
|Flexible||Coral Bells = full sun to full shade Endless Summer Hydrangea = partial shade or dappled sun Wax Begonia = full sun to partial shade|
All plants need sunlight to grow and bloom. However, each plant has a specific requirement for the amount of light it needs for it to thrive. Too much or too little sun may hinder their growth. Therefore, gardeners must understand this requirement and adequately adjust for their plants’ optimum health and growth.
There are tools that can help bring more sunlight into your garden if your sunlight isn’t adequate enough for what you want to grow – I cover them in my post bringing light into shaded gardens.