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Nepenthes turning black


Question
N. inermis
N. inermis  
Hello,

I've got a question concerning my Nepenthes inermis. Some leafs starting to get black (not brown) from the tip. This is commencing up to the stem. Otherwise the plant thrives and gets some offshoots. The 'blackening' is a relative slow process.

The plant is standing in my greenhouse for 2,5 years. The problem started last fall. The temperature lies between 8癈 (lowest possible value) and 35癈, but I cannot say that the process increases with high or low temperatures - it is definitive not burning of the leafs. The plant is standing in bright conditions; during the summer it is lightly shaded. I cannot say anything about the soil, because it stayed in the mix I bought it in.

The water I use is a soft tap water with low mineral content. I live in Germany in a climate zone similar to Oregon.

I think this is a general mistake I am making, because some other Nepenthes of mine have similar issues but in a much smaller extent. Can it be that this is a symptom of to wet conditions ? On the other hand I water the plants frequently, but they are not standing permanently in water trays.

Thank you in advance for your help

Best regards

Achim

Answer
Hi Achim,

Like you soil/potting issues are my first hypothesis on this.  Since you say this is happening slowly it sounds like you may have breakdown of your soil media combined with the original mix being too heavy.  Some nurseries will use coarse peat for Nepenthes, which is fine at first, but it breaks down over time and looses air spaces.  This causes slow root rot.

Try transplanting the plants to new soil media.  Use a mix of long-fiber spahgnum moss with some perlite and orchid bark mixed in.  Many other Nepenthes mixes are used, and as long as they drain fast, yet hold some water, they are fine.  Most Nepenthes are not super picky about their soil as long as it has air spaces in it, and isn't too rich.

After transplanting give them time.  They will need a couple months to recover, and start producing new leaves.  Just cut off any bad ones in the meantime.  Also, check the mineral content of your water.  If the total dissolved solids is above 50 ppm consider using distilled water, rainwater, or water purified by reverse osmosis periodically to flush the soil.

Good Growing!

Jeff Dallas
Sarracenia Northwest
http://www.cobraplant.com

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