We’re used to temperature shifts of 30-40 degrees during the course of a day, but I usually associate that with summer, not winter. But that was our weather last week: lows in the low 30s with highs in the mid-60s, even breaking 70 on Saturday! This requires some masterful layering to be comfortable throughout the day, and depending on how low the temperature goes, some adjustments to our normal routine. If it’s below freezing at the start of the day, we have to wait to harvest most crops until it warms up.
Note: all the photos here were taken after it had warmed up!
Usually we get our first frost around the second week of November. This year it came seven weeks later, after New Year’s day. We appreciate the cold weather. This frost kills off our summer crops (peppers, eggplant, and tomatoes) that otherwise will slowly keep producing. We still had some peppers and eggplant on Thanksgiving! While the plants weren’t dead, we mowed them and planted cover crops in those fields before our break and the rain. Cold weather makes our root vegetables and leafy greens much sweeter; you can really taste it in the carrots. The frost also kills pests, both insects and summer weeds.
Most importantly, our fruit and nut trees need a certain number of chilling hours to bloom evenly and bear a good crop. A “chill hour” is an hour between 32 and 45 degrees. During November and December’s weeks of cold, foggy weather, our trees got lots of time in the mid/low 40s, which may prove to be more beneficial than our current swing between much lower and much hotter temperatures. Warm temperatures too early in the year can be concerning if they cause the trees to bloom too soon and fruit and nut blossoms are very susceptible to freezing temperatures.
These 30 degree winter temperature swings are normal for the Capay Valley. It’s also normal that we have a warm, sunny day while Woodland, Davis, and Sacramento are shrouded in thick tule fog. This spring-like weather is great for growing vegetables, flowers, and winter cover crops! It also helps dry out the soil so that we can get into the field to plant, weed, and harvest without disturbing soil and undoing years of careful work to create healthy soil and good soil texture.
We want some frost, but at the right time. We can handle the frost this time of year. The root vegetables and leafy greens (especially brassicas like cabbage, kale and collards) are cold-hardy and will be fine until about 25℉. Crops like fennel, potatoes, and some lettuce are frost tolerant and will get burnt by frosty temperatures but usually bounce back. Cold temperatures are fine now but that’s not the case later in spring, we’ll have the very vulnerable transplants in the ground for crops that can’t tolerate frost, like tomatoes, and blossoms and baby fruits and nuts on the trees. These times of the year, there’s lots of weather monitoring and if there’s frost in the forecast, we might turn to running sprinklers to utilize the insulating power of water and ice. Not a current concern, fortunately. We’re fine with cold, brisk mornings; the trees need it!
Elaine Swiedler, CSA Manager (with help from Andrew Brait)
