Thanks for the email.
You're not alone. Many of us have dealt with "flakey" volunteers or staff. Staff that just don't follow through with what they started. And it's even more difficult when they are volunteers- because they aren't getting paid for their time.
You asked if it is okay to "push" them. I wouldn't use the word "push" because that conveys being "pushy" or bothersome. But don't be afraid to hold them accountable to what they committed to do.
Sometimes the reason they aren't doing something is a lack of confidence or know-how. Maybe they need someone to "hold their hand" a few times before they do it on their own.
In addition to "hand holding," they might need consistent communication. Not checking up on them, but weekly phone calls of encouragement, letting them know how much you appreciate their help. You can mention specific tasks they did that you appreciate. That affirmation might encourage them to do more of those activities.
Go to my "I Need To Know How To..."
page and look at my recent article on "HOW DO I KEEP VOLUNTEERS?" You'll find more good information on this subject. Also- check out the website I recommended in those articles: www.volunteerpower.com
That is an excellent website dealing with many of these issues as well.
Hope that helps.
The Source for Youth Ministry