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Re: Added Nitrates-Little Happened

On Sat, 8 Apr 2000, Cavan wrote:
> I just can't figure out why some plants grow extremely
> quickly, some grow stunted leaves, and others just
> idle.  It even varies from stem to stem.  Pearling
> isn't too much either.    Wouldn't using the
> Equlibrium and Flourish plus some boric acid take care
> of all nutrients?  Someone mentioned an imbalance. 
> More Flourish? Less?  I am at a loss.  
> I can't think of any toxicity that may be occuring. 
> No nylon is present.  Soap or oil from my hands? 
> Anaroebic areas in the substrate?  Insufficient water
> circulation?  Bad luck?  

Maybe boron toxicity?  I can't tell from your description how much you're
adding, but boron is one to be careful with.

I once planned to dose my tank with boron and figured I'd add enough boric
acid to bring things up to 0.5 mg/l.  Boron-sensitive plants show toxicity
effects at (working from memory without a safety net) about 1 ppm , so I
figured I'd be safe with that dose. Then I got a real analysis of my water
supply and found that it already carried almost 0.5 mg/l.  My safe dose
would have brought the total to 1 ppm and could have killed plants.

There's an excellent article on factors effecting plant growth at


The emphasis of the article is on vegetables grown hydroponically, but
plants are plants, right?  In Table 7 (Toxicity Symptoms for the Essential
Elements) the authors describe boron toxicity as:

"Younger leaves deformed, yellowing or necrosis of leaves beginning at
leaf tip."

Anything sound familiar?

The toxicity of boron to plants is highly variable.  That might explain
why some of your plants are having problems and others are growing very

If you think that you might have reached toxic levels of boron then
probably you should do a *big* water change and then dose with everything
but your boric acid.  If growth returns to normal then you can start
dosing boron again, but your water probably shouldn't exceed 0.3 ppm

Roger Miller