When dry soil is fertilized, roots suddenly are exposed to a very high concentration of nutrients. Clay pots all too often show another kind of salt build-up. As far as has been determined, the salts that collect from hard water do not burn roots or cause plant injury except to acid. When these same plants are introduced into your home, the shock of low humidity causes their leaves to turn brown around the edges. In addition, they may drop flowers and buds.
Some plants never recover from the shock.
That's why people make and use pebble trays. A pebble tray may be nothing more than an old ice-cube tray or plastic dish filled with pebbles and water. Misting foliage several times daily increases humidity temporarily, but in very dry homes it may not make much difference. If your home is quite dry, group your plants together as a last resort in the battle against low humidity. Plants particularly susceptible to harm caused by low temperatures include aglaonemas, dieffenbachias and fittonias.