What to check first
Map the obstacles
Mark buildings, fences, large trees and the proposed bed or pots. Divide a large bed into a few areas if their exposure differs. Include access to water and a workable path so the sunniest patch is also practical to maintain. [1] [3]
Watch the whole day
Check in the morning, around midday and in the late afternoon. For a more useful estimate, add observations between those checks and note when shadows enter or leave. Record direct sun separately from bright shade or scattered light through leaves. [1]
Check the intended growing season
Write the date on the map. Building shadows lengthen as the sun lowers, and leafy trees change the picture. Illinois notes that a spot north of a building can receive summer sun yet lose it in the cooler growing seasons. [2]
Choose the next step for your plant
Make a small observation log
For each spot, list the observed sunny periods and add their approximate duration. Keep gaps in the record marked as uncertain rather than assuming they stayed sunny. Repeat after a clear day if clouds made the pattern difficult to follow. [1]
Match the crop to the measured light
Give crops needing strong light the longest sunny window you can provide. Most vegetables perform best with at least six hours of direct sun. If the location falls short, reconsider the crop or try a movable container in a brighter, accessible spot. [3]
What to avoid
- Do not count every daylight hour as direct sunshine; a bright sky above a shaded bed is different exposure.
- Do not remove a tree or commit to a permanent bed based on one season's midday view.
What to watch next
Keep the first map and compare it after leaves emerge or before a fall planting. If growth later disappoints, revisit the light record alongside water, soil and crowding rather than assuming fertilizer can make up for shade.
Common questions
Do the sunny hours have to be continuous?
Record each sunny interval, even when shade divides the day. The total gives a useful planning estimate, while the timing helps you see which neighboring structures or plants interrupt it. It is still an observation, not a guarantee of crop performance. [1] [3]
Does a south-facing space always get enough sun?
No. Direction is only a starting clue. A building, fence or tree can block a south-facing spot, and those shadows change seasonally. Check the actual place where the plants will grow. [1] [2]
Sources and review
This guide was prepared with AI assistance and checked against the sources below. It has not been reviewed by a botanist. Conditions and plant responses vary; use the checks above to decide what applies. Read our editorial standards.
- Illinois Extension: Make a garden sun chart
Repeated observations and a simple map showing buildings, trees and changing sunlight.
- Illinois Extension: Make a plan
Seasonal building shade and the importance of tall crops not shading neighbors.
- Virginia Cooperative Extension: Planning the vegetable garden
Site light, water access, seasonal observations and placing tall crops toward the north.