With as many as 36 students in some classrooms at Jackson Elementary School in Medford, it will take a lot of patience to make it through the first few weeks of school, said Principal Kelly Soter.

With as many as 36 students in some classrooms at Jackson Elementary School in Medford, it will take a lot of patience to make it through the first few weeks of school, said Principal Kelly Soter.

"Lower class sizes make a world of difference," said Soter, noting kindergarten and third- and fifth-grade classes are particularly large this year.

"At some point, it becomes a physical space issue," said Soter, as she directed dozens of kids across Summit Avenue after school Wednesday.

Soter said district administrators work with schools to determine where extra-large bubbles of students are and how to make the best use of resources to reduce class sizes and make the larger classes bearable.

Medford's enrollment across the district is up by 500 this year, reaching a record-breaking 13,100 students as of Friday.

Thirty of those new students are at Jackson. After last school year ended with 399 students, officials projected an enrollment of 402 students. But by Wednesday, 432 had registered.

"It's crazy. We always fluctuate," said Soter. "It's really hard to guess."

Jason Triplett, who is teaching a fifth-grade class of 36 kids at Jackson, is waiting to find out whether the district will add another teacher, implement a blended class or offer him extra support staff and prioritized time to use larger learning areas outside the classroom.

"It's a matter of coordinating with staff across the district," said Soter. "We need to be patient."

Since mid-August, the Medford district has added four full-time-equivalent teachers at the elementary level and may add more, said Julie Evans, director of elementary education.

"We're filling positions as we speak," said Evans, adding that it takes time to figure out the most effective way to balance uneven class sizes.

"(Students) don't come in nice packages as groups of 27 to 33," said Evans.

Evans said the district had 145 more kindergartners register this year than expected, prompting the creation of four more classes of half-day kindergarten. At 1,034 students as of Friday, it is one of the biggest kindergarten classes in history.

"We were a little surprised," said Todd Bloomquist, director of secondary education for the district. "You really never know until the first day of school."

Bloomquist said he had hired 2.8 full-time equivalent staff Monday to help with large math and social studies classes at the secondary level.

The increase of 500 students across the district comes with expenses but also about $3 million in added revenue, based on an estimate of $6,000 per student in state funding.

That amount will fluctuate based on enrollment statewide, and won't be added to the district's budget until next year.

Administrators have yet to determine the origin of the influx of students, as registration paperwork done at each school site hasn't yet been entered into a database, Bloomquist said.

Typical factors that increase enrollment can include more families moving into the area and students returning to the public school system from homeschooling or private schools.

"I think it's a little bit of everything, it's hard to say," said Bloomquist, noting that Lone Pine Elementary School and South Medford High School, which are in different areas of town, both had a burst in enrollment.

"The market is moving a bit here, that could be a factor," said Bloomquist.

Last year, the district remained relatively flat in enrollment, but attributed small increases to the district's two charter schools, Logos and Madrone Trail.

Enrollment at Logos, which provides instruction options for home-schooled students, is up about 200 students from the same time last year, according to administrator Joe VonDoloski.

The K-12 charter school's enrollment was 759 students Wednesday, the most the school has had since opening with 200 students in 2010.

Of the students enrolling in Logos, VonDoloski said usually about 60 percent come from another public school, while 40 percent are students who were homeschooled.

Districtwide, Bloomquist said there is a particularly large senior class, freshman class and fourth-grade class.

Enrollment typically continues to creep up over the next few weeks, and the district expects it could welcome another 100 students in the next month.

"Our tendency is to increase over the next month or so, and then plateau by October," said Bloomquist.

Reach reporter Teresa Ristow at 541-776-4459 or tristow@mailtribune.com.