How To Determine How Much Sun An Area Gets

Choosing the right plants for your garden or balcony starts with one simple question: how to determine how much sun an area gets. This guide will walk you through easy, no-cost methods to measure sunlight, so you can match your plants to their perfect spot.

Sunlight is the fuel for your garden. Getting it right means happier plants, more flowers, and better harvests. Let’s look at some straightforward ways to become a sunlight detective.

First, forget about guessing. We need to move from “it seems sunny” to actual data. The key is to observe your space over a full day, preferably over a few seasons. But don’t worry, it’s simpler than it sounds.

Gardeners categorize sunlight into four main types. Understanding these will help you speak the language on plant tags.

Full Sun: At least 6 hours of direct sunlight between 10 a.m. and 6 p.m.
Partial Sun / Partial Shade: Between 3 to 6 hours of direct sun. Often “partial sun” means it can handle more intense light, while “partial shade” prefers the gentler morning sun.
Dappled Sun: Filtered sunlight, like under a tree with loose leaves.
Full Shade: Less than 3 hours of direct sun, with mostly indirect light.

The Simple Sun Map Method

This is the easiest way to start. You only need a piece of paper, a pencil, and a sunny day. No special tools required.

Draw a simple sketch of your garden area, including your house, fences, and large trees.
On a sunny day, check your garden at three key times: 9 a.m., 12 p.m., and 3 p.m.
Each time, mark on your sketch exactly where the sun is shining and where shadows fall.
Repeat this on a different day, or even better, in a different season if you can.

By the end, you’ll have a visual “sun map.” You’ll see clearly which beds get all-day sun and which are shaded by structures in the afternoon. This method is surprisingly effective and gives you a great baseline.

The Stone Tracking Technique

For a more physical record, try this clever trick. It’s perfect for tracking sun across a single bed or patio.

Gather about 10-15 small stones or pebbles.
Place them in the area you want to test first thing in the morning.
Every hour, go outside and move any stones sitting in direct sunlight to a seperate pile.
Count the stones in the “sun pile” at the end of the day. Each stone represents one hour of sun.

It’s a tactile method that makes the hours of sun feel real. If you end up with 7 stones, you’ve got a full sun location. If you only have 2, that’s a shade garden.

Using Technology to Your Advantage

Your smartphone can be a powerful gardening tool. While apps aren’t perfect, they provide excellent supplemental info.

Sun Tracking Apps

Apps like Sun Surveyor or Photopills let you see the sun’s path at any time of year using your camera. They’re fantastic for understanding seasonal changes, especially for planning a new garden in winter.

Simple Timelapse Video

Set up an old phone or camera on a tripod (or a secure windowsill). Record a timelapse video from sunrise to sunset. Watching the 30-second playback shows the march of shadows more clearly than periodic checks sometimes can.

Remember, tech is a helper. Always combine its data with your own observations for the most accurate picture.

Seasonal Changes Are Crucial

A spot that’s sunny in June might be completely shaded in December. The sun’s angle changes dramatically.

Summer: The sun is high, creating smaller shadows from buildings but deeper shade from trees in full leaf.
Winter: The sun is low on the horizon, casting long shadows from structures. Deciduous trees lose their leaves, allowing more light through.

This is why observing multiple times a year is ideal. A garden bed that gets full sun for summer veggies might be perfect for early spring bulbs before a tree leafs out.

Understanding Light Quality

Not all sun hours are created equal. The quality of light matters just as much as the quantity.

Morning sun is cooler and gentler. Afternoon sun, especially in hot climates, is intense and can scorch tender leaves. Many plants labeled “partial sun” specifically prefer the morning kind.

Reflected light also counts. A white fence or light-colored wall can bounce a significant amount of light into a space, making it brighter than you might measure with direct sun hours alone.

Putting Your Sun Data to Work

Now that you know how to determine how much sun an area gets, it’s time to use that information. Match your plant choices to your findings.

For Full Sun Areas (6+ hours): Plant tomatoes, peppers, rosemary, lavender, and most flowering perennials like coneflower and salvia.
For Partial Sun/Shade Areas (3-6 hours): Plant lettuce, kale, hydrangeas, hostas, and many herbs like mint and parsley.
For Full Shade Areas (less than 3 hours): Plant ferns, coral bells, astilbe, and certain groundcovers like sweet woodruff.

This matching is the secret to a low-stress, thriving garden. You’re working with your space, not against it.

Common Mistakes to Avoid

Even experienced gardeners can slip up when judging light. Here’s what to watch for.

Only Checking on Weekends: A weekday shadow from a neighbor’s house might not be present on a Saturday. Try to observe on different days.
Ignoring Mature Tree Size: That small sapling will cast a huge shadow in five years. Plan for future growth.
Forgetting About Indoor Light: The same principles apply for houseplants. A south-facing window is very bright, while north-facing offers low light.

FAQ: Your Sunlight Questions Answered

What’s the easiest way to measure sunlight?
The Sun Map method with a paper sketch is the simplest, most effective starting point for any gardener.

How do I check sunlight for my garden?
Use the stone tracking technique or hourly observations over a full day to get a concrete number of sun hours.

Can I use a sunlight meter from the store?
You can, but they’re often designed for photography and measure light intensity, not duration. For plant purposes, your own time-based observations are usually more reliable and cheaper.

My yard gets sun but my plants aren’t thriving. Why?
Check the quality. Intense afternoon heat might be stressing them. Also, ensure the soil and water conditions are right—sun is just one piece of the puzzle.

How does sunlight change with the seasons?
Significantly. The sun is lower in winter, creating longer shadows. Observe in both summer and winter for the complete picture, especialy near structures.

Final Tips for Success

Start small. Test one bed or corner this weekend. The process is simple and actually quite enjoyable—it makes you pay close attention to your space.

Keep a garden journal. Note your sun findings and which plants succeed where. Over the years, this becomes your most valuable gardening tool. It’s personalized data no app can give you.

Don’t be afraid to move plants. If something is struggling, it’s likely in the wrong light. Use your new skills to find it a better home. Gardening is an experiment, and sunlight is you’re most important variable.