Too much fertilizer
There is such a thing as too much of a good thing — fertilizer, for example. In house plants, such as the dracena in the photo, too much fertilizer can cause the leaf tips to turn yellow and eventually brown. The soil surface or pot rim may develop white or gray deposits that look like salt.
If you suspect your plant has received too much fertilizer, the best thing you can do is run clean water through the pot several times. Let the water run through the soil and out into your sink or use a hose outside.
If the water drains slowly, switch the plant to a container with better drainage. While you’re at it, use new potting mix when you repot to give your plant a fresh start. You won’t be able to reverse the leaf damage that’s already been done, but you can keep it from happening to new growth. Dilute your fertilizer mix to half the concentration you’ve been using to prevent this from happening again.