The best way to ensure success in planting is to put the right plant in the right place. In addition to learning about your soils and site, you’ll also want to do a sunlight assessment before planting. But what if you aren’t sure how to determine the type of sunlight that is shining on your property?

The Importance of Sunlight

Plants evolved to thrive in certain levels of sunlight, but what happens when they’re not planted in the right place?

Too Much Sun: A plant that has too much sun will often show signs of stress on its foliage, like scorched leaves (brown or crispy), pale or bleached leaves, or drooping upper stems during warm seasons. The plant may drop leaves completely, and in extreme cases, may suffer from dieback or not survive at all.

Not Enough Sun: A plant that doesn’t have enough sun will likely be smaller and less dense than it has potential to be. You may notice stems are “leggy”, meaning the leaves and nodes are spaced out more than normal. This is a tell-tale sign that the plant is stretching towards the sun because it’s not getting enough. In extreme cases (think a needled evergreen in shade), the plant could have significant dieback or death. Certain ornamental features may be diminished, for example: a flowering shrub that wants full sun may survive in partial shade, but will have less flowers than you would see if it had been planted in the right place.

Plants that are stressed are more susceptible to other issues like pests, disease, fungus, decreased vigor, or low fruit and flower production.

What sunlight does my plant want?

Most outdoor plants will come with a tag that specifies the type of sunlight they thrive in. Plants are often labeled using 4 categories of sunlight:

• Shade – less than 2 hours of direct sunlight
• Partial Shade – 2-4 hours of direct sunlight or filtered light
• Partial Sun – 4-6 hours of direct sunlight
• Sun – 6 or more hours of direct sunlight

If your plant is not labeled with sun requirements, check out our Plant Research Library to learn more.

Sunlight Mapping on your Property

Step 1: Observe the area over the course of the day.

The best way to determine sun exposure is to observe the planting area over the course of the day. Note what time the sun begins shining on the area, and what time it stops. If there are obstacles fully blocking the sun, such as a building, you may find that your planting area is shaded for a portion of that time.

Step 2: When does the area receive the most sunlight?

A common way to estimate sunlight in your planting area is to determine light by cardinal direction. While this is not the only indicator of sunlight, where your planting area is in relation to your house can help you determine the time of day that is the sunniest.

• South-facing gardens: typically get the most sun exposure, and may be the hottest and dryest part of your property.
• North-facing gardens: typically get the least sun exposure, and may be the coolest and dampest part of your property.
• East-facing gardens: typically get the first sun earliest in the morning, and avoid the direct sun during the hottest parts of the day in the afternoon.
• West-facing gardens: typically are shaded in the morning, and will get direct sun during the afternoon.

Cardinal directions can also be misleading if you aren’t gathering all of the data you need. For example- you may have a large evergreen tree on the South side of your house that shades out your garden bed for most of the day. You may also find that when planting on the North side of your house, a garden bed several feet away from the foundation or on the West corner gets plenty of light for a partial sun plant.

Step 3: Is the sunlight filtered through trees or buildings?

An obstacle like a deciduous tree will provide filtered light to your area during the growing season, but will not block any light during Winter. Sunlight shining through the canopy of these trees is referred to as “filtered light” or “dappled light”. If your planting area has deciduous trees nearby, you may find that you can make a better estimate during the growing season (when trees have their leaves). Filtered light may not seem bright, but it does contribute to the overall light your plant is getting! Some filtered light over a planting area may allow for a partial shade plant to thrive in an area that is mostly shade. Filtered light also may help give a much-needed break from the hot afternoon sun that a partial sun plant is looking for. When you are making your observations, it’s best to note how many hours of direct sunlight shine on a planting area, in addition to how many hours of filtered light it receives.

Step 4: Is the site protected from hot afternoons?

This is a question that you may be able to answer using cardinal direction, but the most accurate way is to observe your planting area in the afternoon. Hot, direct afternoon sun in the summertime may be great for some plants and too stressful for others. Knowing this can help you choose the right plant for the right place. For example- imagine you have garden beds on the East and West sides of your house that have a similar number of hours of sunlight. A plant like Hydrangea macrophylla that gets heat stressed during hot, scorching summer afternoons may be happier on the East side where the sun is in the morning sun and the temperatures are cooler, even though the garden beds have the same total hours of sunlight.

The best way to truly know your planting area is to work through our Plan Your Project Checklist. It is important that you take the time to assess the setting and the soils at the location you are looking to improve.