Thomas G. Chastain

Willamette Valley seed producers have endured yet another cold and wet spring.  Seed growers are now looking forward to the pleasant dry and warm summer weather that area is well known for to aid in harvest and other field operations.  This spring’s weather was both colder and wetter than the long-term averages for the locale.  And this combination of cold and wet weather in spring is part of a trend that has been evident for the past four years.

The weather for April was the first above-average spring month in terms of temperature since June 2009, but the rest of the spring months were colder than the long-term norms for Corvallis  (Fig. 1).  March was particularly notable in that the weather was more typical for mid-winter rather than the normally temperate weather characteristic of the Willamette Valley.

The spring season also brought very wet weather again to the valley (Fig. 2).  Not only was every month wetter than normal, but March was the second-wettest ever for the month since record keeping began in 1889.  Consequently, soil moisture levels are much wetter than normally observed going into the harvest season.  Our previous work with irrigation in tall fescue and perennial ryegrass seed crops has shown that irrigation at peak flowering maximized seed yield in these crops.  These wet conditions may contribute to a very good grass seed crop this year.

Precipitation at Corvallis has increased by about 3 inches during the past 121 years with most of that increase recorded during the spring months.  Colder, wetter springs may delay crop development – learn more here.  Moreover, the timing of field operations such as planting in vegetables and other spring-planted seed crop may be hampered by wet soils.   Some pests such as rusts in grass seed crops may be lessened under wet and cool conditions reducing fungicide applications, but the incidence and severity of others might increase.  Wet conditions increase the need for plant growth regulator use in grass seed crops – something that has become standard practice for many grass seed producers.  These trends and their potential implications for seed production will continue to be monitored.