10/7/11

E-mail- Brown leaf tips

I have noticed the tips of my leaves have brown tips.  What does this mean and if it is a problem how can I fix it?

Thanks for your question.
Browning of leaf tips or leaf margins (leaf edges are called margins) can be caused by a few different things. The first thing I would guess being an indoor gardener is a lack of humidity. If you don’t have one, you should think about getting a thermometer with a min/max setting for temperature and humidity. I have one that takes the humidity reading on a remote wire. I like this because you can put the sensor by your plant tops near the light to be sure the temperature and humidity are in their optimal range by the plant tops, and then you can put the base by your plant pots/floor to see what the humidity and temperature are down there. If you use an HPS or MH these bulbs generate a lot of heat (which can also cause leaf tips to burn) and also reduce humidity. This low humidity can be good as low humidity is bad for spider mites (LINK) and fungal disease, but also not the best situation for your plants. If you do have low humidity (30% or less) I think this may be something (brown leaf tips) you may want to live with. You can mist your plants, have the pots sit in trays with stones and standing water and water you plants a bit more often, but all these can have negative side effects. If the brown tips do not get worst, or you do not see other leaf discoloration the best thing might be to do nothing.

Brown leaf tips and brown along the margins can also be a sign of fertilizer burn and/or poor water quality. If you are using more than the recommended amount of fertilizer the brown tips are a sign you should not add more or reduce the amount of fertilizer. If your water has high amounts of chlorine or chloramines you could consider a water filter. Lastly, if you are using an insecticidal soap this may cause brown leaf tips.
Please feel free to send me any more questions if you have them.
Good Growing,
Dr. E.R. Myers

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