Bolton & Menk, a civil engineering firm, will bring in 58 interns this summer — a record number.

“It’s a great opportunity for them,” said Celeste Voss, the Mankato-based company’s talent acquisition specialist. “It is like a three-month job interview.”

The healthy crop of interns also is a great opportunity for Bolton & Menk, which employs 420 in Minnesota and does myriad engineering and planning work throughout the Upper Midwest. The employee-owned company, which ranked 20th on the Star Tribune Top Workplaces list of midsized companies, is feeling the squeeze from a U.S. unemployment rate at a 50-year low.

The labor market “is tighter than it has ever been,” Voss said.

Like Bolton & Menk, several midsize companies — those with 150 to 499 employees — surveyed by the Star Tribune reported that tight labor markets have been endemic the past few years. In response, they’re all upping their recruiting game.

Minnesota employers are coping with a hot economy coupled with a workforce that is growing so slowly it’s become a hindrance for hiring. Indeed, Steve Hine, a labor market analyst from the Minnesota Department of Employment and Economic Development, noted this spring that the paucity of workers is keeping a lid on state job growth rates.

Still, midsize employers canvassed by the Star Tribune say that while they’re feeling the labor pinch, their output has not been affected.

For some executives, though, the thought of a production squeeze has crossed their minds.

“We are definitely concerned about it,” said Mark Gibbs, managing partner of Redpath and Co., an employee-owned St. Paul-based accounting firm that also has an office in White Bear Lake.

Redpath has 158 employees, and, like Bolton & Menk, it’s growing. “We need more people generally and we are hiring at a record pace,” Gibbs said.

With the tight job market, Redpath just hired its first 100% “mobile” employee — an accountant who works completely at home, in this case North Carolina. Previously, Redpath has allowed some employees to work at home, but only after starting at one of the company’s offices.

Redpath, which was fifth on the midsize company list, does much of its hiring through recruiting at several colleges in Minnesota. The company often reaches out to students in their freshman or sophomore years. “We invite them in for a day to get them introduced to Redpath early in their college careers,” said Sarah Gengenbach, the company’s human resources director.

Five years ago, such an invitation would have been aimed at juniors and seniors, she said, but it has been extended as the accounting labor market has grown tighter.

”Juniors and seniors are eligible for internships, which in turn often lead to job offers,” Gengenbach said. Just a few years ago, the company would have hired interns for the tax season during the preceding September. Now, Redpath will line up internships a full 18 months ahead of time to make sure they can fill the positions.

Bolton & Menk and Glacial Ridge Health System also recruit at several schools.

“Having good relationships with colleges and universities is key,” said Bolton & Menk’s Voss. The company’s employees are encouraged to reach out to their alma maters. Some sit on advisory boards at engineering schools they attended, Voss said.

Glenwood, Minn.-based Glacial Ridge — a nonprofit that operates a hospital, three clinics and an eye care center — has a particular relationship with nearby Alexandria Technical and Community College. Nursing students essentially do on-the-job training, racking up clinical time at Glacial Ridge that counts toward their degree at Alexandria.

“As far as recruitment, that is a definite benefit,” said Diane Meyer, Glacial Ridge’s marketing and communications manager.

Glacial Ridge, with 360 employees, has been growing while labor markets have been stretched. It employs 24 physicians and advanced-practice providers — almost five times as many as in 2006 — and about 90 nurses and nursing assistants.

Glacial Ridge, which was second on the list, also owns and operates its own ambulance service, and paramedics and emergency medical technicians (EMTs) are also particularly hard to find. “I think every ambulance service around the country is struggling to get EMTs and medics,” Meyer said.

To help with recruitment, Glacial Ridge recently worked with the Glenwood Lakes Chamber of Commerce in an effort to identify people who grew up in the area and still have family there — and who might want to return. Also, the company is working to improve its digital job-marketing efforts.

Employees can also be critical to recruiting, too, just through referrals. “Employees are the best source to know if someone will fit the culture,” Meyer said. Glacial Ridge is considering an employee bonus for referrals.

ACI Asphalt & Concrete, 21st on the list, started giving referral bonuses 18 months ago. “Our strongest recruiting effort comes from word-of-mouth,” said Jeremy Quinn, general manager of Maple Grove-based ACI, which does pavement work and includes many heavy equipment operators among its workforce of 160.

ACI’s referral bonuses are $25 when a prospect is interviewed; $50 if that person is hired; and $250 if he or she stays 90 days. “We have some people getting two or three bonuses,” Quinn said.

Employee referrals are a good way to find new workers “who would be a good fit for our culture.” And the company has built a strong culture — including an increasing focus on work-life issues — to recruit and retain workers, Quinn said.

“These days if you don’t have the right culture, nobody will come work for you.”