Yacolt — For two days in April, kids were encouraged to dig in the dirt. First-graders at Yacolt Primary School learned about the importance of worms in the ecosystem from Washington State University master gardener volunteers on April 29 and April 30. Eight classrooms participated by picking through compost to get a close look at how worms — including night crawlers, earthworms and red wigglers — help decompose organic waste. The children are studying the topic in science classes.