Microclimates are small pockets of climate variations that differ from the surrounding climate. By identifying and using microclimates you can grow fruit and veggies not normally recommended for your climate zone. Pay attention to the way the sun travels across your property throughout the season. Look for cold spots and hot spots. A maximum-minimum thermometer placed at different locations will tell you a lot about your microclimates. Here are a few other things to look for.
Slope - the Banana Belt Effect – Cold air moves like water, so in spring and fall a valley floor will usually be significantly colder than a slope. Some slopes are called banana belts, because they remain frost-free much longer than valley floors, which may be subjected to hard frosts, a common phenomenon in the Mid Klamath. Banana belts occur in areas with at least a 3 ½ % slope (150 feet/ mile) that is 100 to 200 feet higher than the nearest spot where frost can settle. These banana belts can be 8 – 15 degrees warmer on frosty nights. Utilize this if you are in a cold climate and are concerned about frost damage, make the best use of slopes when available.
Aspect - A south-facing slope is, of course, much warmer than a north-facing slope. Western slopes receive the hotter, more intense afternoon sunshine, while eastern slopes receive the less intense morning sun. A south facing wall is a good place to plant a tree that needs extra heat in order to ripen. If the wall has an overhang, it will also provide some frost protection. The influence of aspect can become dramatic in the winter when some north facing slopes and drainages may receive little or no sun; these areas often retain frost all day long on the shortest days, while adjacent areas with a different aspect may be warm and sunny.
Treeline, Ridgeline & Shade- The steep valleys and tall conifer forests of the Mid Klamath region create lots of shaded areas. Shade can be an asset in the long, hot days of summer, creating microclimates for crops that are less heat tolerant; and a liability in the winter, when shaded areas may never see the sun and retain ice and frost the entire day.
Thermal mass – Water and stone will absorb heat during the day and re-radiate it at night. A stone or brick wall can be an ideal place for ripening a late fruit crop. Translucent jugs of water placed in a greenhouse or around fruit trees will re-radiate heat at night. A small pond will serve as a heat sink in the summer and fall, and a cold sink in spring and winter. Watering before an anticipated frost will increase re-radiated heat – the wet soil will absorb more heat than dry soil during the day, and release more at night.
Wind – Strong wind can dehydrate plants, damage fruit and decrease air temperatures. Wind protection can be especially important in coastal or desert regions. The best windbreak is one that slows wind down rather than stopping it. A solid wall set perpendicular to prevailing winds will result in lots of turbulence on the downwind side. Hedges, vines, lattice fences and screens allow some wind to pass through without creating turbulence.