Say the title of this post out loud – Germination Day…. To me, when I hear it, it sounds like it should be a holiday. I’m willing to admit that this may be because I’m a sheepman who relies on annual rangeland to feed my sheep – and because I’ve lived through a prolonged drought – but I like the idea of taking a day off when our annual grasses finally germinate in the fall. I certainly celebrate when our golden Sierra foothills turn to green!
Our annual grasslands need 0.5-1 inch of rain to germinate in the fall. For more than 40 years, the folks have kept track of such things at the Sierra Foothill Research and Extension Center (SFREC) in Browns Valley, CA. Based on their records, a germinating rain has arrived sometime between late September and early November (on average). This soaking rain is needed to get the seeds of our annual grasses to sprout. For most of the lands that we graze near Auburn, 0.75″ of rain is enough to get the grass started.
Continued growth depends on a number of other factors. Once the grass has germinated, we need a good mix of sunny days and continued rainfall to keep it going. We also need conditions that help keep moisture in the soil – dry north wind, for example, will dry out our soils. Cooler weather – and cold storms – also cool the soil. We need soil temperatures of greater than 50 degrees F to keep the grass growing. Regardless of the autumn rains and weather conditions, we always reach a point in early December where we simply don’t have enough daylight to grow grass – the days are too short for photosynthesis.
Based on these considerations, an ideal autumn for me is one in which we get a germinating rain before our irrigation water shuts off in mid-October. This first rain is followed at regular intervals (perhaps once a week) by moderate rainfall (0.33-0.75 inches) interspersed with sunny days. These conditions allow for enough grass to grow before we reach winter dormancy. At that point, we have to manage our grass carefully to get through to the resumption of growth that usually occurs in February. If the grass gets an early start in the fall, we have more to work with through the winter!
Here in Auburn, we had our 2019 germinating rain on September 16. Now, just over a week later, our grass is starting to grow! On the other hand, this week’s warm and windy weather has resulted in drying conditions. Looking ahead at the forecast, I’m hopeful we’ll pick up some additional moisture in the next week. We’ll see!
Early germination isn’t always ideal, nor is fall precipitation always a good indicator of how the year will turn out in terms of forage production. In 2013, we had a germinating rain in early September, followed by a lengthy dry spell. This early germinated grass died for lack of moisture. We then had another germinating rain in mid-October, again followed by a dry spell. The grass germinated again, but didn’t grow much. Finally, we had a very cold storm in early December, followed by 50+ days of no rain at all. When it finally rained again in late January 2014, it took 45 days before we actually had enough green grass to graze our sheep.
Nor does an early start to fall weather excite every farmer. I spoke with a rice grower in Lincoln after last week’s storm who told me the wind and rain had lodged (or laid over) much of their crop, making harvest more difficult. And invariably, a late spring or early autumn rain ruins someone’s hay crop.
Those of us who rely on Mother Nature’s provenance are conditioned to uncertainty – we never know for sure what the rainy season holds in the Sierra foothills (or anywhere else, for that matter). Despite this uncertainty – or perhaps because of it – I am always excited when we get our germinating rain in the fall. I always celebrate Germination Day!