Replacing graduating seniors

[FWinter]

My team is relatively small (<20 students, 2 mentors) but looking to grow in the near future, as we only have 2 seniors this year and have had large freshman recruiting classes over the last few years. However, one of these seniors has been our sole programmer for 2 years. There have been 3 other students that have (sometimes half-heartedly) tried to learn from him, but one of these quit and of the other 2, one has mimimal experience and training and the other isn't particularly interested in programming. One thing I've figured out, even as a member of the build team, is that programming (and therefore, good programmers) is rather important. With this in mind, I'm looking for ways to get a head start on "replacing" him.
Neither of our mentors is a programming mentor and our team does not have extensive offseason programs in which to learn/teach more. Our school does have a newly formed "Coding Club" that we might look to for new members, but I don't foresee this being highly effective.
Could people please recommend some training resources and/or ideas for recruiting new programmers?
Thanks!