Preparing the Terrain for Fences
Fences make a landscape much more comfortable and enjoyable. They provide shade, help light up dark areas, and reduce strong winds to gentle breezes. As you conduct your inventory of fencing needs, take into account sun and wind patterns in your yard and identify areas that could use protection. Note those places on your sketches.
Study first, build later
Your yard is full of microclimates— small areas where temperature, sun patterns, and wind velocities differ from general conditions.
If you want fencing to increase shade, plot the course of the sun across your yard. Stake out shade patterns at different times of the day. Remember that the angle of the sun changes with the seasons. The winter sun is low in the southern horizon, so it casts shadows during much of the day. In the summer, shade can all but disappear from 10 a.m. to 3 p.m.
Include prevailing winds as well as seasonal breezes in your wind study. Prevailing winds blow from the same general direction over your region. Seasonal breezes are more localized and occur only at specific times of the day, intermittently during a season.
Fencing with the sun
The amount of shade a fence creates depends on its height, its proximity to the shaded area, and its axis. Tall, solid fencing can shade nearby decks, patios, or garden plots with special plants that require only partial shade. Lattice panels make dappled shade; acrylic panels will let in all the sunlight.
If you need constant shade throughout the year on the north side, build the fence on an east-west axis.
Fences will reflect light too. If you paint the sunlit side of your fence with a light color, sunlight (and heat) will bounce into a nearby planting bed—a useful tool for gardeners whose spring planting might be ruined by a late frost. A fence built to improve privacy will send warm light into a nearby south-facing room if you paint it a light color.
Controlling the wind
Wind—like water—takes the path of least resistance. It spills over objects and creates micro conditions in your landscape. Fences can adjust these conditions to your benefit.
For example, wind that blows across a patio surface and into the corner of the house creates eddies that swirl and dump debris before they move on. You can control the
prevailing wind to minimize the effect of those eddies, but don’t expect a solid fence to help much.
Wind-control research shows that wind swirls over the top of solid objects and drops back down at a distance roughly equal to the height of the fence. Solid fences create low-pressure pockets that pull the wind down into the area you want protected.
Fences with gaps or openings in the surface, such as board on board, grape stakes, spaced slats, basket weave, or lattice, filter the wind and slow it so it passes through in a pleasant breeze. A solid surface that blocks the wind would cause it to vault over the fence and blow down the other side with turbulence.
Snow fence design—the object of substantial research over the last 30 years— has become a science in itself. Here are the three types:
- Plastic snow fence: Introduced in the 1960s, plastic snow fence is effective at containing snow. It has a serviceable life span of five years (longer if taken down between seasons) but requires considerable maintenance.
- Lath fence: Also called Canadian or “cribbed” fence, it’s made of 1/2-inch lath wired in 25- or 50-foot rolls. It’s longer-lived but not as effective as plastic or Wyoming snow fence.
- Wyoming snow fence: Made of 1x6s spaced 6 inches apart, starting 10 inches above the ground, Wyoming snow fence will last 25 years or more, is as effective as plastic, and requires minimum maintenance.
Snow fence should run in a straight line, parallel to and centered on the area that you want to protect. It’s best to orient it perpendicular to the prevailing winds and at a distance from the protected area equal to roughly 30 times its height.