Philodendron problems

Hello,

I have a philodendron in my classroom that I brought in from the store last year.   It has grown considerably since then, but the growth seems stalled for a reason I can't quite identify at the moment.  Some leaves are turning yellow and wilted which makes me think that they are getting too much water (it certainly is not dry).  On the other hand, the new growth at the tips of some of the vines are starting to get black, dried curls, suggesting a lack of water.  When I give more water, the black tips go away but the yellowing worsens.  One thought that I had was that it has become root bound and needs a larger pot to sit in since it hasn't been repotted since I bought it.

Thoughts?

Eric

If the plant is pot bound, repotting would be the next thing to try. When plant roots are bound, the root hair zone has moved to the outer part of the root ball and makes little contact with the potting mix for constant supply of moisture and nutrients.  When there's nothing else wrong with light, temperature and pest, rejuvenating root growth usually solves the problems with container plants for me.