How To Determine Sun Exposure In Yard

Figuring out how to determine sun exposure in yard is the single most important step you can take for a thriving garden. It’s the difference between plants that flourish and those that just survive. This guide will give you a simple, hands-on method to map your yard’s light so you can choose the right plants for every spot.

Sunlight is the fuel for your garden. Too little, and plants become leggy and weak. Too much, and they can scorch or wilt. By understanding the unique patterns in your space, you can work with nature, not against it. Let’s get started.

This process requires a little observation, but it’s not complicated. You’ll need a simple sketch of your yard, a pencil, and a few days to watch the light. The goal is to create a “sun map” that shows you exactly what happens in your garden from morning to evening.

What You’ll Need to Get Started

A notebook or a few sheets of paper.
A pencil (you’ll be erasing and redrawing).
A ruler or straight edge.
Your phone’s timer or a simple watch.
A few sunny days in a row for best results.

Step 1: Draw a Basic Map of Your Yard

Don’t worry about being an artist. Just sketch the rough outline of your property. Include all the permanent features that cast shadows. This is the foundation for your sun map.

Draw the outline of your house, garage, or shed.
Add fences, walls, and large, permanent trees.
Mark the cardinal directions (North, South, East, West). Use a compass app on your phone for this.
Divide the yard into zones (e.g., “back left corner,” “along the west fence,” “patio area”).

Step 2: The Four-Observation Method

Pick a day with clear weather. You will check your yard four times, noting where the sun and shadows fall. The times are flexible, but aim for these general windows.

Morning Observation (8–10 AM)

Go outside and look at your sketch. Which areas are in bright sun? Which are in shade? Lightly shade in the shadowed areas on your map with a pencil. Label this area “Morning Shade.” Areas in full sun get no shading.

Midday Observation (11 AM – 1 PM)

Repeat the process. You’ll notice shadows have moved or shrunk. Update your map, noting new shaded areas. This is often the most intense light of the day. Pay special attention to areas that were sunny in the morning but are now shaded.

Afternoon Observation (2–4 PM)

Check again. The sun is moving westward, casting long shadows from eastern structures. Update your map once more. This observation is key for identifying the hot, western sun exposure many plants are sensitive too.

Late Afternoon Observation (5–6 PM)

Take a final look before the sun gets to low. This helps you understand the total daily duration. Some spots might only get sun in the early morning and late evening, which is still considered shade.

Step 3: Define Your Sunlight Categories

Now, analyze your map. Most gardens will have areas that fit into one of four standard categories. Use these definitions to label each zone on your final map.

Full Sun: 6 or more hours of direct sunlight. This area recieves sun during the midday period.
Partial Sun / Partial Shade: 3 to 6 hours of direct sun. Morning sun with afternoon shade is often called “partial shade,” while afternoon sun is “partial sun.”
Full Shade: Less than 3 hours of direct sun. This doesn’t mean no light—it means dappled light or only brief periods of direct sun.
Deep Shade: No direct sunlight and very little reflected light. Often under dense evergreens or in narrow passages between buildings.

Step 4: Account for Seasonal Changes

Remember, the sun’s path changes. The observation you did is a snapshot, likely from spring or summer. For a truly optimal plan, consider these shifts.

In winter, the sun is lower in the sky. Areas that are sunny in summer might be in complete shadow. Conversely, areas under deciduous trees (trees that lose leaves) will have full winter sun but dappled summer shade. This is a great oppertunity for spring-blooming bulbs.

Step 5: Test with Sun-Loving Plants

If you’re still unsure, use a simple plant test. Place a potted, sun-loving annual like a marigold or zinnia in a questionable spot. Watch it for a week or two.

If it grows compact and flowers well, it’s likely full sun. If it grows tall and leggy, reaching for light, it’s probably partial sun or shade. This real-world test can confirm your map.

Putting Your Sun Map to Work

Now for the fun part: choosing plants. Your map is your most valuable gardening tool. Always match the plant’s light needs to the zone on your map. The plant tag is your best friend here—don’t ignore it.

Plants for Full Sun Zones

These are the sun worshippers. They need that intense energy to bloom and fruit properly.

Most vegetables (tomatoes, peppers, squash).
Herbs like rosemary, lavender, and thyme.
Flowers like coneflower, salvia, and black-eyed susan.

Plants for Partial Sun/Shade Zones

This is a versatile category. Many popular perennials thrive here with protection from the harsh afternoon rays.

Hydrangeas (especially macrophylla types).
Hostas and coral bells (Heuchera).
Vegetables like lettuce and kale, which can bolt in too much heat.

Plants for Full Shade Zones

These plants have adapted to lower light. Their beauty often comes from fantastic foliage, not flashy flowers.

Ferns, like autumn fern or lady fern.
Bleeding heart (Dicentra).
Astilbe and foamflower (Tiarella).

Common Mistakes to Avoid

Even experienced gardeners can make errors with light. Here’s what to watch out for.

Guessing Instead of Mapping: Don’t rely on a single glance. Our perception of light is often wrong.
Ignoring Reflected Heat: A south-facing white wall can create a “heat sink” that intensifies sun exposure, potentially scorching plants labeled for “full sun.”
Forgetting About Tree Growth: A sunny spot today might be shaded in five years as trees mature. Plan for the future.
Overwatering Shade Plants: Shady areas dry out much slower than sunny ones. Overwatering is a common cause of failure in shade gardens because the soil stays wet to long.

FAQ: Your Sun Exposure Questions Answered

What if my yard gets mostly morning sun?

Morning sun is cooler and gentler. This is ideal for “partial shade” plants. Many vegetables and flowers that can’t handle hot afternoon rays will do beautifully here.

How do I check sunlight in my garden?

Follow the mapping method above! It’s the most reliable. You can also use a sunlight calculator app, but nothing beats direct observation over a few days.

Is afternoon sun stronger than morning sun?

Yes, typically. Afternoon sun is hotter and more intense because the air and soil have warmed up throughout the day. A plant that tolerates 4 hours of morning sun might wilt in 4 hours of afternoon sun.

Can I increase sun exposure?

Sometimes. You can prune lower tree branches to let in more light or use reflective materials (like light-colored mulch or stones) to bounce light into darker corners. Removing entire trees or structures is a bigger project.

What’s the easiest way to measure garden sunlight?

The simplest way is the “hour tracking” method. On a sunny day, note when a specific spot lights up and when it becomes shaded. Count the total hours of direct light. Repeat for different areas.

Taking the time to determine your yard’s sun exposure is an investment that pays back every season. It saves you money on plants that won’t thrive and reduces frustration. With your personalized sun map in hand, you can plant with confidence, knowing you’re giving every plant the best possible start. Your garden will thank you with better growth, more blooms, and a healthier ecosystem.