Homestead mailing list

[Bill Jones <billj AT harborside.com>]

Bill Jones wrote:

> EarthNSky wrote:
>
>  
>
> > Bill Jones wrote:
> >
> >
> >
> >    
> >
> > > It that why my greenhouse, where it never rains at all, has a layer of 
> > > white alkali just as in a desert?
> > >   
> > >
> > >      
> > Unless you are watering with distilled water, your water contains 
> > mineral salts and various ions.  As you water, these leach out and 
> > create that white stuff on the pots and such.  The moisture in the 
> > greenhouse alone may be enough to leach out the minerals from the 
> > potting mix/soils, creating white salts.
> >
> > Bev
> >
> >
> >    
I should point out that my greenhouse has no "moisture" to speak of.  
It's entirely open at the ends, so it only serves to raise the heat some 
in summer, and keep the rain off in winter.  It's drier than the 
surroundings, since it's hot in there in summer.  The white salts come 
from the repeated evaporation of irrigation water.

Do you remember Moira Ryan from OGL?  She was very well informed about 
most aspects of organic gardening.  She observed, correctly, that this 
salt buildup consititutes the greatest challenge to agriculture in 
desert areas, and there's no real way around it, without enough water to 
leach them away.

Bill
S. Oregon coast