We have many flavors of wind on the west side of the Sacramento Valley. Some are large-scale phenomena that affect the entire region while others are more localized. Each one of them has a profound affect on the climate here at the farm, and thus, on the crops we grow.
Our farm is just 30 miles from the Carquinez Strait, which funnels moist marine air from the ocean into the Central Valley. When it is cool in the Bay Area and hot here, the Delta Breeze cranks up and provides us with natural air conditioning every evening. This generally keeps Terra Firma from getting quite as hot as other parts of the Central Valley in the summer. Among other things, these cooler nights mean that we use less water to grow summer crops than other farmers in our region. But there are downsides as well: in late summer, the nights get a little bit too cool and dewy, which causes problems with crops like tomatoes and melons.
In the spring and sometimes winter, the marine air is warmer than the dry air here. So the Delta Breeze can also keep the nights from getting as cold as they do just a bit north of us. This is why we are able to harvest peaches and tomatoes as much as a month earlier than other areas even in our own county where the risk of frost damage is much higher.
Then is the Anti-Delta Breeze. When a storm passes to the north and into Nevada, it generates a north wind that dries the air and sucks moisture from trees, plants, people and the ground. The terrain of our area, located along the east side of the Coast Range, accelerates and magnifies this wind. While it affects the entire Sacramento Valley, it is often far stronger here in Winters, gusting well above 30 miles an hour. Worse yet, it generally lasts a full two or three days at a time.
Over the last twenty years, we have lost dozens of crops to the north wind, which can occur just about any time of year. In the winter, it can freeze-dry leaves as well as the rinds of citrus. In the spring, it can easily kill small plants, blow off blossoms of fruit trees, berries and tomatoes, and break tree branches. One year, we lost most of our pistachio crop to a north wind on Labor Day that hit the orchard just a few days before harvest, knocking all the nuts onto the ground.
Finally, we have our own highly localized wind caused and influenced by the terrain and microclimates. Nicknamed the “Berryessa Breeze”, it flows downhill from the reservoir located just 10 miles west and 500 ft. above us in the hills. It generally gets going around four o’clock in the afternoon as a gentle breeze trickling through Putah Creek Canyon, but by the time it reaches Winters around 6, it’s often strong enough to blow your hat off.
This time of year, the wind can be a constant force affecting our farm, clocking from south to west to north to east and then back to south. Sometimes it is subtle. For the last several weeks though, it has been a nearly constant. We’ve had to schedule activities like transplanting and irrigation around the wind, which has been extremely challenging. Last week we had a raging north wind one day followed by a very stiff Delta Breeze the next. While we try not to irrigate on super windy days due to evapotranspiration, we had no choice last week as the plants and trees were drooping every afternoon.
There has been one large upside to the back-and-forth, cool-then-hot weather this spring: it has allowed us to keep harvesting a wide diversity of crops. In a week or two, we may actually have both lettuce and tomatoes in the same CSA box — a feat we rarely accomplish in the spring.