Hi --
Years ago it was believed that crushed walnut shells poison the soil for
garden plants. Is this still the prevailing wisdom?
Have an abundance of shells from a gift box of walnuts received from CA.
Seems wrong to just toss in the garbage. Always thought what came from the
ground should be returned to the ground, but I don't want to hinder the growth
of my garden plants.
TIA (Z6,NJ)

"Twobtold" wrote in message
...
Hi --
Years ago it was believed that crushed walnut shells poison the soil
for
garden plants. Is this still the prevailing wisdom?
Have an abundance of shells from a gift box of walnuts received from
CA.
Seems wrong to just toss in the garbage. Always thought what came from
the
ground should be returned to the ground, but I don't want to hinder the
growth
of my garden plants.
TIA (Z6,NJ)

You shouldn't have anything to worry about. Black walnuts, as do a number of
other members of the genus, excrete a hormone - primarily from the roots -
which can hinder the growth of sensitive plants. English walnuts possess
this hormone in much lower concentrations and even less so through the
shell. And how large a gift box are we taking about ? It can't be too many
shells to begin with. If you have any concerns, use them for informal
pathways.

pam - gardengal

Gee, Twitbetold. For someone from New Jersey you ask a lot of stupid
questions.

There is no problem using walnut shells as mulch providing you do a thorough
job of pulverizing them!!! So get yourself a hammer and smash the crap out
of them. Its good stress relieving therapy for the holiday season too.


"Twobtold" wrote in message
...
Hi --
Years ago it was believed that crushed walnut shells poison the soil
for
garden plants. Is this still the prevailing wisdom?
Have an abundance of shells from a gift box of walnuts received from
CA.
Seems wrong to just toss in the garbage. Always thought what came from
the
ground should be returned to the ground, but I don't want to hinder the
growth
of my garden plants.
TIA (Z6,NJ)

You shouldn't have anything to worry about. Black walnuts, as do a number of
other members of the genus, excrete a hormone - primarily from the roots -
which can hinder the growth of sensitive plants. English walnuts possess
this hormone in much lower concentrations and even less so through the
shell. And how large a gift box are we taking about ? It can't be too many
shells to begin with. If you have any concerns, use them for informal
pathways.

pam - gardengal

Use of Waste Products

Synthetic mixes may use organic ingredients that once were classed as waste
products - conifer bark and redwood sawdust. Although these particular
ingredients have been thoroughly tested for toxicity, pH reaction and
uniformity, other waste products also can be used."What comes out of the soil
should go back into the soil," say conservationists, but gardeners do not
always agree. While it is true that crushed almond shells, as well as grape
pomace (when composted) can be used safely as a soil amendment, walnut leaves
or crushed walnut shells poison the soil for garden plants. Sunflower seed
hulls look promising, but tests have proven that they contain some
growth-inhibiting properties. Any organic material, especially agricultural
by-products, must be tested carefully to ensure that it contains no toxic
elements.
Resource: The American Horticulture Society Illustrated Encyclopedia of
Gardening Ó1981
March 1991 Chemung
March 2000 Revised

Hi Pam --
Above is from Cornell site citing AHS's encyclopedia, but it's from 1981.
Thanks for your reply, helpful as always.
It was a 20 lb. box. I guess the quantity of the left over shells would
appear different to different people.
Thanks again

"Twobtold" wrote in message
...
You shouldn't have anything to worry about. Black walnuts, as do a
number of
other members of the genus, excrete a hormone - primarily from the
roots -
which can hinder the growth of sensitive plants. English walnuts possess
this hormone in much lower concentrations and even less so through the
shell. And how large a gift box are we taking about ? It can't be too
many
shells to begin with. If you have any concerns, use them for informal
pathways.

pam - gardengal

Use of Waste Products

Synthetic mixes may use organic ingredients that once were classed as
waste
products - conifer bark and redwood sawdust. Although these particular
ingredients have been thoroughly tested for toxicity, pH reaction and
uniformity, other waste products also can be used."What comes out of the
soil
should go back into the soil," say conservationists, but gardeners do not
always agree. While it is true that crushed almond shells, as well as
grape
pomace (when composted) can be used safely as a soil amendment, walnut
leaves
or crushed walnut shells poison the soil for garden plants. Sunflower
seed
hulls look promising, but tests have proven that they contain some
growth-inhibiting properties. Any organic material, especially
agricultural
by-products, must be tested carefully to ensure that it contains no toxic
elements.
Resource: The American Horticulture Society Illustrated Encyclopedia of
Gardening Ó1981
March 1991 Chemung
March 2000 Revised

Hi Pam --
Above is from Cornell site citing AHS's encyclopedia, but it's from
1981.
Thanks for your reply, helpful as always.
It was a 20 lb. box. I guess the quantity of the left over shells
would
appear different to different people.
Thanks again


I'd say that quote was a little simplistic at best. Allelopathy is common to
a great many plants, but in varying degrees and most often, affecting only
certain target plants. To say that walnuts "poison the soil for other
plants" is a bit of a misstatement. The hormone that walnuts - and primarily
black walnuts, Juglans nigra - excrete is concentrated in the root system
and can inhibit the growth of only certain plants. Concentrations in leaves
and shells are significantly lower. And since the effect is limited to only
certain plants, primarily those in the Solanaceae, it can hardly be said to
"poison" the soil. English walnuts, Juglans regia, possess juglone in a much
lower concentration, so the effect will be even slighter.

And a 20 lb box is not enough shells to worry about, regardless. I use
hazelnut shells on my pathways and a 50 lb sack of those is just a drop in
the bucket - it hardly covers anything.

pam - gardengal