Tony wrote in message ...
I read somewhere that too much fertilizer can accumulate in leafy vegetables to
the point of being toxic for human consumption, does anyone know where I can
find out more about this, especially as it relates to hydroponics? I read this
in a book on green houses, it said something about problems with nitrogen not
being used up by the leafy vegetables in certain times of the year and thus
accumulating in the edible parts of the vegetable.

-Tony

It is true that some leafy greens, already a good source of proteins,
could get their nitrate levels so high as to irritate people with a
delicate digestive tract. That is why you don't want to give broccoli
to a baby younger than 1 year (ditto for chard). For most of us, it is
not a problem. One serving of broccoli has 5g of proteins and far far
less in the way of nitrates. Compare with a steak...