Banana tree question
Plant Growing Conditions: Indoors, in a pot with full sun exposure to the north. I have worried that perhaps it was getting too much sun. I water it 2-3 times a week and have been fertilizing it every other watering cycle. It is not growing a new leaf every week as you mentioned in your article.
What I've done already: I notices spider mites and used Safer Insect Killing Soap twice. I didn't see any improvement so I switched to Sevin Bug Killer.
Doug says
Let's deal with the problems in order. The lower leaves dying are quite typical of banana. They die from the bottom at about the same rate as they are produced from the top. Your description of dying from the edges in sounds quite typical. Simply prune off the leaves when they get too ugly.
Having said that - brown edges on new leaves sounds like the house is too dry - not enough humidity in the air for this plant. That browning is typical of tropical plants grown in too low a humidity.
White substance on the leaves doesn't sound like the dying process in any way. Could be a variety of things - possibly powdery mildew. Banana will get this. Banana are also beloved by scale (eliptical brownish 1cm spots on leaves) and mealy bug (that looks like small cotton batten). It is also "possibly" water evaporation from getting the leaves wet and having the water evaporate leaving calcium spots behind. This depends on your water quality. It's tough to diagnose that without a picture but generally speaking, it is the least of your concerns at the moment. The big one is the mites and the second is the humidity.
If the plant isn't growing quickly, we're likely looking at a low light condition. Northern exposure is way too little for good growth. This baby needs full southern. This is a tropical plant that is used to high light conditions. While it might be optimistic to suggest a leaf a week indoors, in the natural light conditions, this is a fast growing plant.
Watering - use the finger test (water if finger comes away dry, leave alone if finger comes away from soil damp) to determine how much water it requires. Feed weekly during the growing season (high summer light) and back off in the cooler, darker months.
Ah, the dreaded spider mites. Frankly, I stopped growing banana plants in the greenhouses when I had my nursery and in my house because they are spider mite traps. Spider mites love this plant like I like chocolate. Big time!
Getting rid of spider mites on banana plants is pretty much a non-starter once they're established. You can knock them back with darn near anything you want to spray them with and they'll be back. I don't care if you use Sevin (I'd never use that btw and particularly in the house) :-( or Insecticidal soap - it is only a temporary remedy. You'll have to spray almost every 5-7 days for a month to see any real knockback (with soap or chemicals). One or two sprays isn't going to do the job.
I hope that helps a bit - let me know if you need further clarification on any of these points.
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