Your company started with a vision. You and your inner circle brought it to life. Now, you need managers to make it grow.

Hiring from within rewards excellence and generates loyalty. But promoting a member of your support staff to the role of manager is risky. If he or she has never managed people before, inexperience could lead to turnover, bad attitudes, and poor results.

Here's how you can help make sure none of that happens:

Become a mentor. Not just for the first week, but for as long as it takes until you are confident your new manager is where you need him or her to be. Provide feedback frequently, and be available as needed in case he or she runs into a situation that's new.

At my firm, we established a peer consulting program that helps managers expand their internal network. If a problem crops up that they are unsure how to handle, they can reach out to more experienced managers in other divisions or regions. They can even be assigned a peer coach who can work with them directly to develop on-the-job skills. Every quarter, this network of managers get together to strengthen their relationships and skills.

Establish a timeline. This is meant to help your manager transition into the new role. Set a definite time--60 or 90 days--so it's not open-ended. We do a skill assessment at the start, middle and end of this period to help us and the manager assess progress.

Create opportunities to learn. According to CEB, 10% of development is from training, 20% from peers, and 70% from coaching while on the job. So creating opportunities for continual learning is essential for new managers. My firm holds two-day training classes every quarter for our managers. We also have a new-management curriculum covering such topics as managing staff remotely and handling difficult conversations. We have found that updating topics is important in creating and retaining great leaders.

Invite their decisions. Employees promoted to manager roles often need time to earn the confidence and respect of co-workers they worked with before being promoted. It's up to them to establish personal and professional boundaries, but you can help strengthen their credibility around the office by asking their advice in front of others, relying on their input, and making it clear to others that you are deferring decisions to them.

Let them fail. We all learn from failure. They will too. Treat early missteps as growing pains, and use each situation to show new managers what to do next time. Pretty soon, things will go exactly how you want them to go--next time and every time.

You can't grow a company by doing everything yourself. To grow, shift your mentality from growing your company to growing your managers so they can grow your company for you.

Correction: An earlier version of this column incorrectly referred to CEB as its former name, the Corporate Executive Board.