> we heard
> some disturbing information about the build-up of nitrates in greens,
> including lettuce, other salad greens and cooking greens (especially
> Swiss
> chard).
>
Everything in the goosefoot family (spinach, beets, lambsquarters) tends
to accumulate nitrate. I didn't know that lettuce could accumulate so
much, but according to the literature it can. But keep in mind that
people don't eat that many pounds of greens a month, and so the dose of
nitrate may not be all that large.
Nitrification inhibitors might be useful to control soil nitrate in
certain circumstances.
> Specifically, we were advised that it is inappropriate to pick
> lettuce and other greens in the morning (that is when we like to pick
> , in
> the cool of the day) as nitrates can build up to serious levels over
> night;
> exposure to 4-6 hours of sun dissipates the nitrate concentration.
>
How practical is this advice?
> After going to the "trouble" of growing these crops organically we do
> not
> want to introduce toxins unintentionally.
>
Toxins are part of life, but dose is what is important.
I pulled out a bunch of literature references on this subject. If
anyone wants them, let me know. One possibly useful tibit I found: You
can measure this inexpensively using an ion-selective electrode.
Dale
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