It’s hard to believe that just four weeks ago today, it was pouring rain while I wrote the newsletter. The high temperature that day was 54 degrees. Yesterday it was sunny and hot, reaching 88 degrees and today is likely to hit 90. That change has been as sudden for the crops as it has been for us humans.
Over the course of those four weeks, we went from checking fields every day to find someplace where the soil had dried out enough and waiting for the mud to dry, to checking fields to see which needed irrigation. As of today, every crop on the farm — other than the orchards — has been watered at least once and many twice or even three times.
That’s not to say that things are truly “dry”. The drought conditions we experienced in 2022 and 2021 are gone. A foot down, the soil is still sticky and wet. But most of the vegetables we grow can’t access that moisture, especially the ones we’ve planted in just the last few weeks.
We’re starting irrigation season in great shape. Groundwater levels appear to have rebounded strongly from the levels of the last few years. With near-record setting rains, our creeks and streams were running for several months, which is the most important factor in groundwater recharge in our area. It also helps that no one was pumping any water out of the ground during that long time period.
Our primary source of irrigation water at Terra Firma is not groundwater though. It’s Lake Berryessa, which supplies water to our irrigation district. Like most reservoirs in the state, it is over 90% full now after dropping to just about 50% last fall. In layperson’s terms, the lake added over two years worth of supply this winter.
Unlike the reservoirs on the eastern side of the valley, there is no giant snowpack in the mountains above Lake Berryessa. So we have a “best of both worlds” scenario where the reservoir filled almost entirely this winter without any flooding. That’s unusual.
Wet winters create a positive feedback loop. Irrigation season starts later, and crops don’t need as much water. That is true not just of orchard crops, but also of summer crops like tomatoes and watermelons which have deep enough roots to access residual soil moisture. And of course overwintered crops got all their water from the sky for the last six months. That is true not just of crops we grow like onions and garlic, but also of wheat grown by commodity farmers.
The long rainy season did have some detrimental impacts for a few of our crops: both our strawberries and our tomatoes are way behind schedule in their growth and will be late in arriving. However, the deep moisture in the ground will help keep many other crops strong and healthy during the summer and into fall
While farmers across the state will likely plant far more acres than they did during the drought, just about all of those crops will be grown using stored water from reservoirs. Irrigating this way helps recharge the groundwater even further.
By the time the rainy season starts again in the fall, it’s very likely that California’s reservoirs will still be in great shape and groundwater levels in many areas will still be much higher than they have been in years.
But until then, we’ll be busy trying to keep everything irrigated!