There are no problem to use dehumidifier water for your plants. That water
contains very few minerals.
>
> The only problem I can forsee is the presence of
> metals and metal oxides in the water due to the
> condenser coils etc. Primarily aluminium and zinc.
> Perhaps iron also.
>
these metal are not very toxic for most plants. In fact plant need aluminium
in oprder to produce blue pigment for flower and leaves. When you ad
aluminium to red pigment you get blue pigment. Aluminium is absorbed by
root at a pH around 5.5 to 6.0. away from that range aluminium is not
absorbed very well by plant and in fact phosphorus absorbtion will interfere
with al absorbtion. Water from dehumidifier is around 7.0 like distilled
water and at that pH al wont hurt. Also phosphorus souce used for fertiliser
production contains lot of aluminium but nobody know it. For other metal
like Zinc and iron, it will be so little that the plant wont get enough from
that source alone.
So use it and save your distilled water.
thanks, Claude