Sun Requirements For Plants: A Complete Guide

The sun provides us with the energy we need to power our homes, fuel our crops, and still have more than enough left over for everyone else. But what happens when we remove things that used to absorb the sun (i.e., plants and trees) for the built environment? All the energy that once went into trees and native grasses now cooks our roads and heats our cities.

As a homeowner, you can change that. The right plant at the right place can make all the difference in the world. But how do you know where to place which types of plants? Have you ever wondered what labels like "full sun" and "partial shade" really mean? Let's look at the various levels of sunlight and see what we can plant to absorb some of that extra energy.

Full Sun

A plant requiring full sun doesn't have to be in direct sunlight all day. "Full sun" typically means the plant needs at least six total hours of direct sunlight on most days. Some plants prefer additional light hours and are generally hardy to the heat and drying power of the afternoon sun. Species such as this often require these conditions to produce buds and flowers and do well on the west side of the home. For plants that need full sun but are sensitive to heat, consider planting them to the east side of the house in an un-shaded area.

Many annuals and perennials enjoy full sun, including plenty of favorites from the home garden! For the most sun on the property, plant to the south of the house (in the northern hemisphere).

Sometimes the full sun can be a curse. Do you have a driveway that absorbs the summer heat? Consider planting some trees or even a hedgerow between the asphalt and the sun's path. Hedges can be used in suburbs and cities to help offset the effects of urban heat islands. Planting deciduous trees along the southwest to the west side of your house will block the afternoon sun in the summer, keeping those rooms slightly cooler. And since deciduous trees lose their leaves in the winter, this will allow extra light and thermal radiation when we need it the most in the winter.

You can also consider using vining plants to create a canopy blocking the direct full sun. Consider adding edible vine varieties like grapes and kiwis to your home's pergola, giving you and your guests both shade and snacks as you relax in the backyard.

Part Shade / Part Sun

Plants that adapt to partial shade and sun require between 3-to-6 hours of direct sunlight. These will typically be plants that are sensitive to afternoon heat and sun and need additional protection.

With plants that prefer partial sun, be sure to meet their minimal sunlight hours. These numbers will vary from plant to plant, so pay attention to any particular recommendations. For partial-shade, be sure to plant in places that will be protected from the early afternoon overhead sun. Locations on the east side of the home that provide ample cool morning and early afternoon light will be ideal.

Finding the right place for partial shade plants requires trial and error. So if a plant isn't reacting to a site as intended, don't be reluctant to try again elsewhere.

Occasionally, there are parts of the yard that are left bare because we don't know what to put there. One of these spots might be near the fence that defines our property lines. Growing plants directly on the fence can be problematic, so consider placing a trellis a few inches away and training some plants on it.

If you have an east-facing fence, consider placing trellised peas and beans. This will create an edible wall for your family to snack. Consider sunflowers on your west-facing fence. These flowers will thrive with the extra sunlight and intense afternoon heat. They act as an attractant to birds and butterflies, and at the end of the season, you will be gifted some homegrown sunflower seeds. (That's if your feathered guests don't get to them first!)

Dappled Sun

"Dappled sun"—meaning the sun that filters through tree canopy above—is similar to, or slightly less than, "partial shade." Plants that like "dappled sun" are relatively uncommon. The types of plants adapted to the dappled sun are typically understory species found in woodland areas. These plants are also the ones that you will see growing under trees in the early spring while the branches are still bare.

If you're looking to fill in under your food forest, consider plants like the Daylily. This versatile perennial does well in full sun to shade and can do well as an understory plant. With heavy canopy cover, the plant will see a reduced yield of flowers but still grow.

In dappled sun conditions, whatever you plant will have to contend with other species planted around it. Be prepared for some plants to survive and others to struggle. It will be up to you to determine what's working and not working and then adjust appropriately.

Full Shade

Full shade doesn't mean no light. Instead, it's referring to plants that manage on less than 3 hours of direct sun. These are typically plants that grow on the north side of the house.

You can incorporate several plants into the backyard that can take advantage of the sun (or lack thereof). And with proper placement, we can cool our property and even produce a crop where there previously wasn't one. So be creative in your gardens next year. The sky's the limit!

Article by:

Tanner Sagouspe

Tanner Sagouspe has a Masters in Environmental Management and is a Permaculture Designer who promotes tackling the climate crisis at home.