Light Matters: Mapping Sun And Shade In Your Yard
Sunlight is critical to successful gardening. Because too much or too little light is a frequent cause of plant problems, many nurseries organize plants by how much sun or shade they need. Before falling in love with a gorgeous new plant, take time to size up your yard. Light conditions change throughout the day and across seasons, and will likely vary across different areas of your garden as well.
Did you lose trees during Hurricane Helene?
If so, your yard’s light exposure probably changed. Losing even a single tree or large shrub can open up new areas of full sun, potentially exposing shade plants to light they can no longer handle. Similarly, the growth of an existing tree or the addition of a new structure (such as a tool shed or garage addition) can add shade to previously sunny spots.
How much sun or shade?
The North Carolina Extension Gardener Plant Toolbox classifies sun requirements of plants into four categories:
Full sun: Six or more hours of direct sunlight a day- Partial shade: 2 to 6 hours of direct sunlight (with shade dominating the rest of the day)
- Deep shade: Two or less hours of direct sunlight per day, as with heavily wooded areas
- Dappled sunlight (filtered shade): Light is filtered through tree canopies, creating some patchy sunlight through foliage
Of course, not all sunlight is alike. In North Carolina’s hot summers, morning sun is gentler, while afternoon sun can cause heat overload. Planting areas next to asphalt, concrete, or other heat-absorbing materials will be even hotter.
Some nurseries distinguish between “partial sun” and “partial shade” plants. While definitions vary, most growers suggest that partial sun plants prefer slightly more sun than partial shade (4-6 hours, vs. 2-4 hours). In general, partial shade plants need more protection from the afternoon sun than do partial sun plants.
Keep in mind, even plants labeled “full sun” may struggle in the afternoon heat of July and August. Likewise, partial and deep shade plants are more tolerant of morning than afternoon sun.
Create a sun map for your yard
The best way to get a sense of the light patterns in your yard is to spend a day mapping them. Start early in the morning and check each garden area on the hour. Record the level of exposure, taking note of both sun and shadows. Here is a sample of a completed sun map.
If possible, construct your sun map in different seasons. Remember that a sunny spot in March may be shaded in May by a nearby tree filling out with leaves. On the flip side, a shady area in the spring may gain exposure as the sun climbs higher in the sky and days lengthen.
Here is a handout on sun mapping that offers different mapping strategies. For more detailed information, watch this brief associated video.
What about edibles?
When it comes to edible crops, sun is essential.
- Most vegetables require at least eight hours of full sun. Some leafy greens—lettuce, kale, spinach—or root vegetables— radishes, turnips, beets—can get by with six hours of sunlight, but will perform better with more.
- Herbs usually need six hours of full sun, but some, such as cilantro, mint, and parsley, can tolerate less.
- Cane berries (blackberries, raspberries) prefer at least eight hours of full sun, but some berries, such as blueberries and strawberries can manage a bit of shade.
Gardeners are fond of the expression, “Right plant, right place.” By taking the time to understand light patterns in your yard, you’ll make wiser and healthier planting choices.
Article written by Melissa Himelein, Extension Master GardenerSM volunteer
For more information:
Sun and shade requirements
- Basic Plant Care: Understanding Your Plant’s Needs (see “plant light requirements” section)
- North Carolina Extension Gardener Handbook, Woody Ornamentals (see “site characteristics” section)
- Vegetable Gardening: A Beginner’s Guide
- Growing Herbs (see light requirements on Table 1)
Sun mapping
- Sun to Shade: Changing Light Patterns in Your Garden (video)
- Sun to Shade: Changing Light Patterns in Your Garden (handout)