Sun Mapping Your Garden
Contributed by Jolene Ottosen for the Chaparral Green Thumbs
When you go to buy plants, either perennial or annual, you will see that they are often divided by sunlight needs.
● Full Sun: 6+ hours
● Partial Sun/Partial Shade: 3 to 6 hours
● Full Shade: Less than 3 hours
Sometimes it is easy to know what category different parts of your yard fall into, but some areas are deceptive and can get more or less sun than you actually realized. Regardless of whether you are planting an Arbor Day tree or something else, to help get the most from your space and really get to know the light in your yard, you might want to make a sun map. There are different ways to sun map, and they can be as high or low tech as you want them to be.
In its most low-tech form, sun mapping involves making a rough, to-scale, sketch of your yard and then choosing a sunny day to observe the sunlight. Starting as close to sunrise as you can, go out every hour or two and lightly sketch the shadow lines in your yard, making sure to record the time for each set of lines. Using a tape measure will help you get the most accurate results. By the end of the day, you can then look back and calculate how much sun each area of your yard receives throughout the day and therefore which types of plants would be most suitable. Of course, the length of our days and the height of the sun changes quite dramatically throughout the year in a northern city like Calgary, so you will want to measure the sun at a variety of times over the growing season.
If drawing is not your forte, you could use a camera and tripod instead. Set up the tripod in the morning and take photos from the same spot at regular intervals throughout the day. You could also use the time-lapse feature if your camera has it. Then, you download the pictures and use a computer program to change the opacity, so each layer of pictures is slightly more opaque (see through) than the next. Then, by stacking the images on top of each other, you get an idea of what areas have full sun all day, partial shade, and full shade. A set of marking flags from a hardware store could help you to mark a rough grid to easily show distances in your photos.
If you want to get really serious, you could spend a few hundred dollars on a Solar Pathfinder, which will help you get the most accurate results but requires some calculating and looks more involved than I would care for. Another tool option is to order a cheaper sun mapping kit that includes a small device that looks much like a calculator and is left in an area for a twelve-hour period, measuring the light. You can only do one area of your garden at a time with this, and it gives a range, not an exact number of sunlight hours, but you can just put it out and forget it, which works better for some.
Regardless of the method that works for you, if you are willing to take the time to map out the sun in your yard, you might find a few surprises and get a little more out of your space.
If you are interested in more information about the garden, email us at [email protected].
Click here to the Chaparral Community News home page for the latest Chaparral community updates.
