They sell fancy gadgets to map the sun patterns in your yard, but it's not too tough to simply jot down shade outlines on a map a few times a day.  I opted to measure at 10:15 am, 1:30 pm, and 4:30 pm to get a good overview of the peak sun hours.  (Well, to be honest, I forgot I'd planned to make a sun map or I would have drafted an earlier morning map as well, and by supper-time, I wanted to be done with the project.)

My goal was to figure out which parts of the yard count as full sun, partial sun, or full shade around the summer solstice.  When gardeners talk about full sun, they mean an area that receives at least 6 hours of direct sunlight during the peak sun period (when you'd want to be wearing sunscreen): between about 10 or 11 am and 4 or 5 pm.  Partial shade/partial sun generally refers to 3 to 6 hours of sun, with less of an emphasis on getting that sun during peak hours.  (In fact, some partial shade plants might burn to a crisp in bright afternoon sun.)  Full shade generally means that an area only gets light dappled through trees, perhaps with a couple of hours of direct sunlight.

When naming the type of sun in your garden, though, you also have to take your distance from the equator into account.  There's a reason that growers in equatorial areas came up with the concept of forest gardening and placed vegetables under their trees --- scorching sun in Mexico might be so extreme that "full sun" plants would prefer quite a bit of shade during the early afternoon.  On the other hand, if you live in Alaska, I'm not so sure that an hour of sun around noon would even count as half an hour of full sun.

Finally, there are more complex issues to consider.  Plants prone to fungal diseases (like tomatoes) really should get hit with sun early in the morning to dry off their leaves.  Meanwhile, I'm considering planting a peach or two in an area with only afternoon sun to slow the trees down in the spring so their flowers don't get nipped by frost.  And partial shade can be handy for eking spring crops out in the summer heat, especially if the vegetables are only bearing leaves.  (Leafy vegetables, in general, need less sun than vegetables who will be asked to produce fruit.)

If you have a graphics program that allows layering and transparency (I use the free program GIMP), it's simple to merge all of your day's maps together and decide which parts of your yard get what kind of sun.  As you can see from the composite image below, our clearing in the forest gets full sun only in the very center, with the east end shaded by trees in the morning and the west end shaded in the afternoon.  The powerline cut provides a bit more of a full sun zone, and the spot behind the barn where we recently felled some trees to dry up the barn wall has a little pocket of full sun as well.

Of course, the patterns change dramatically throughout the year, so I'll make another map at the winter solstice, if I remember.  (Maybe at the equinoxes too.)  I know from the melting pattern of snow that the sunniest winter areas are quite different from the sunniest summer areas, with most of the warmth being concentrated in the mule garden.  (There's a big hill on the south side of our core homestead, so when the sun dips lower in the winter sky, it doesn't reach the southern parts of the yard much.  On the other hand, leaves are off the trees during the winter, so the forest giants edging our core area block less light.)

Hopefully getting a better handle on sun and shade patterns will help me fill in the gaps in our homestead most efficiently.  Already, I'm eying that area behind the barn for some kind of plant, and am realizing that the coop for the poor broilers is in the sun all day long.  Aren't maps fun?

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About us: Anna Hess and Mark Hamilton spent over a decade living self-sufficiently in the mountains of Virginia before moving north to start over from scratch in the foothills of Ohio. They've experimented with permaculture, no-till gardening, trailersteading, home-based microbusinesses and much more, writing about their adventures in both blogs and books.



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