Question
Hi:
I have a lot of mineral deposit on my orchid leaves (phaleas., dendrobiums, oncidiums, etc.) and I was wondering if there was some way to remove it.  I have tried soaking leaves with de-ionized water and then using a wet tissue to remove the build-up without success...  Any suggestions would be welcomed.
Thanks.
James

Answer
Hi James,

Those mineral deposits are from your water supply which is probably considered "hard" water.  To remove those ugly deposits you can try using citric acid (be sure to wear protective gloves when you use it).  If you do not happen to have pure citric acid laying around (grin), you can use the juice (no pulp) from a lemon, orange or grapefruit.  Dip a clean cloth in the juice, fold it over the leaf covering both the top and bottom surfaces, then gently (do not grip the leaf too tightly) wipe the leaf from the bottom to the tip of the leaf.  To get the deposits from the crotch of the leaves, dip a Q-tip in the juice, remove most of the juice before wiping.  If the deposits are really bad and do not come off easily, it may take several cleanings but do not try using more pressure as that can damage the leaf surfaces.  

You can also use slim or low-fat milk to do the same cleaning operation.  Do not use whole milk because it contains fats that can end up looking as ugly as the mineral deposits.  

To minimize future buildup of mineral deposits, try watering your orchids at the top of the pots rather than from above the leaves.  

Hope this helps.  Good luck and good growing.  

Jim Kawasaki
San Jose, Ca.