By creating a simple map of your shade you will get a clearer picture of the true level of sun exposure in your garden. To do this right, you need to do it at least twice in the year – once in the summer and once in the spring or fall. If you really want to understand your exposure, map in all four seasons at the equinox and solstice.
First thing to do to understand the available sunlight in your garden space, is to map your shade. Mapping the shade in your landscape is a very useful tool in landscape design. If you want to succeed in your garden endeavors, you should know where you have sun and where you don’t.
How to map your shade:
- Using graph paper layout the buildings and large trees on your property. Don’t worry about being totally exact, but be mindful with spacing and relative sizes.
- With your map in hand visually watch and map the shade pattern by checking the yard at 9 am, noon, and 3 pm. This will give you three points to connect to make the arch of shade movement.
Remember these things when interpreting your map:
- Shade moves clockwise (sun-wise) (northeast interpretation)
- The more objects the more shade – note the overlapping that occurs
- The denser the object the denser the shade – house shade is totally dense, trees with big leaves have denser shade than trees with small leaves.
- Evergreens case shade year round
Deciduous plants (ones that lose their leaves) cast a denser shade when they are in full leaf and a light shade when they are leafless. Notice leaf size too!
Now with the shade in your yard mapped you are ready to determine whether you have:
- Full sun – 6 plus hours
- Part sun – 4-5 hours of sun
- Part shade – 2-3 hours of sun
- Full shade – less than 1 hour of sun
Common errors that are found in the sun mapping:
- Seeing sun and believing that space is sunny.
- Seeing shade and believing that space is shady. Just because you notice sun or shade on a parcel of land, doesn’t mean that this area will be hospitable to plants that prefer sun to shade or vice versa.
There is a logical reason behind this, which we have noted below:
- The sun moves from sunrise (east) to sunset (west)
- The angle of the sun is changing with the seasons
In the northern hemisphere (New England in particular) the height of the sun (or solar altitude) is changing roughly 50 degrees in relation to the horizon over the year. So this means the sun is far higher in the sky in the summer (creating shorter shadows) than in the winter (longest shadows). Starting in the winter the solar altitude increases through spring and peaks in summer then it begins to decrease through autumn to its lowest point in the winter sky.
Where you live on the globe matters! It’s not wildly different…you have the same sun after all, but as to the reality of rise/set and angles you might want to go to a better source. Read about Earth-Sun Geometry to know more!
Incorporating the above facts about sunlight when you get into garden landscaping and planning will help you know how the sun’s rays effect your garden. The reality is most of us usually have something or the other that will cast shade. Many of us have plants etc too. If we don’t…then people living close to us certainly do.
Thus the importance of sunlight mapping in landscaping is very important!