Question
What causes the topsoil in my indoor potted plants to turn yellow and become crust-like? All of a sudden my indoor plants started doing so poorly, I don't know if this is a symptom of something else.  Thank you for your time.  
Leeann Miller


Answer
Leeann,

It sounds like you are not watering enough and as the soil dries out it leaves behind dissolved salts, either fertilizer or from the water itself.  

When you water your plants you should apply enough water so that about 20% -30% of the volume you apply drains out the bottom of the pot.  this will ensure that the entire soil profile is wetted.  Do this over the sink and leave the plant there until the water stops draining, about 5 minutes.  If you do this while the pot is in a saucer the soil will stay too wet because the water has no place to go.

If you are unsure about whether to water, give your plant the finger.  No that finger.  Take your index finger and stick into the soil down to your first knuckle.  Only water if the soil feels dry.

Good luck

Gary